I Paid Cash and Have the Invoice. Could This Be a Problem for MTD ITSA?

​

Professional guide for sole traders, CIS subcontractors and Romanian builders in the UK: private jobs, cash receipts, materials, duplicate invoices, shared costs and fabricated documents

​

For many builders and tradespeople in the UK, the situation appears simple:

“I bought the materials or tools, paid cash and received the invoice. Can I include the expense in my accounts?”

In principle, yes.

Making Tax Digital for Income Tax does not prohibit cash payments and does not require a sole trader to pay every expense through a bank account or with a business card. A genuine purchase made for the business and supported by credible documents may be deductible regardless of whether it was paid by bank transfer, card or cash.

However, the invoice does not create an automatic right to a deduction.

For an expense to withstand an HMRC check, there must be a coherent connection between the supplier, the purchaser, the goods or services received, the payment made, the source of the money, the business purpose and the accounting record.

The risk increases when cash expenses cannot be reconciled, private jobs are paid in cash but not declared, the same invoice is used by several people, or the document has been altered or fabricated.

Cash is not the main problem. The problem arises when the records cannot demonstrate the genuine transaction and cannot explain where the money came from.

Who Does MTD ITSA Apply To?

MTD ITSA applies to individuals who receive income from self-employment and property. It is not the system through which a limited company reports Corporation Tax.

Within the Romanian community, the phrase “I bought it through the business” is frequently used even when the person operates as a sole trader. Legally, however, a sole trader and their business are not two separate entities in the same way as a limited company and its director.

MTD ITSA is being introduced in stages. People whose qualifying income from self-employment and property income exceeded £50,000 in 2024–2025 must enter the system from 6 April 2026. The threshold falls to more than £30,000 from April 2027 and to more than £20,000 from April 2028. Qualifying income essentially means the relevant gross income before expenses are deducted, not the net profit. (GOV.UK)

For those entering the system in 2026–2027, the first quarterly update must be submitted by 7 August 2026, followed by deadlines on 7 November, 7 February and 7 May. Quarterly updates contain category totals for income and expenses; they are cumulative summaries, not complete tax returns or copies of every invoice. (GOV.UK)

What Does MTD Change, and What Does It Not Change?

MTD changes the way records are created, retained and submitted to HMRC. It does not change the fundamental tax principles concerning whether an expense is genuine and deductible.

A digital record must be created for each item of income or expenditure and must include the amount, date and relevant category. The records must be kept in compatible software, while original documents or copies of them — such as invoices, receipts and bank statements — must be retained separately to support the return. (GOV.UK)

A photograph of an invoice may be attached to the software, but the photograph does not replace the digital record itself.

A bank feed can simplify the process, but it is not compulsory. HMRC also states that some transactions will not appear fully in the bank feed and must be recorded separately. Responsibility for the accuracy of the records remains with the taxpayer, even where the software is connected directly to the bank account. (GOV.UK)

This is particularly important for builders because cash receipts and payments do not automatically appear in the account.

Paying Cash Does Not Automatically Make an Expense Non-Deductible

For most sole traders, the cash basis is now the default method for calculating profit unless the individual chooses traditional accounting. Under the cash basis, income is recognised when it is received and expenses when they are actually paid. (GOV.UK)

Therefore, if you receive an invoice in March but pay it in cash in April, the tax timing of the expense will generally be determined by the payment date when you use the cash basis.

The payment method and deductibility are, however, two different issues.

The expense must be genuine and incurred for the business. If the item is also used personally, only the business element can be claimed. For example, if a £1,200 laptop is used 75% for business and 25% personally, the full invoice amount does not automatically become deductible; the business proportion must be separated under the applicable rules. HMRC allows the deductible proportion to be recorded directly or the full amount to be recorded and followed by an adjustment for the personal element. (GOV.UK)

The Invoice Is Important, but It Does Not Prove Everything

A genuine invoice demonstrates that a supplier states that a sale took place. On its own, it does not always prove that the person claiming the expense received the goods, incurred the cost, used them for their own business and did not pass the same invoice to somebody else.

For a significant expense, the file should allow the transaction to be reconstructed. In addition to the invoice, relevant evidence may include the receipt confirming the cash payment, the delivery note, order confirmation, project address, communications with the supplier, photographs of the materials or tools and the connection with the job for which they were purchased.

This level of documentation is particularly important for builders, where similar materials may be bought for several projects and some products may also end up in the builder’s own home.

An invoice from a builders merchant for £3,000 does not automatically prove that the entire amount was used for customers. If £500 of materials was used at the builder’s own home, that element must be excluded from the business expenses.

Private Jobs Must Be Declared in Full

A builder may work simultaneously as a CIS subcontractor for other businesses and directly for private homeowners, landlords, developers or managing agents.

Private jobs can include extensions, loft conversions, kitchens, bathrooms, roofing, plastering, painting, paving, fencing, landscaping, plumbing, electrical work and many other services.

The fact that a job is called a “private job” does not mean that the income is private or non-taxable.

A private householder who hires a builder to carry out work on their own home is not normally a contractor for CIS purposes. The private customer does not need to verify the builder and does not deduct CIS at 20% or 30%. However, the amount received by the builder remains business income and must be declared in full. (GOV.UK)

The absence of a CIS deduction does not turn the income into tax-free money.

Example: Private Job Paid Partly in Cash

A builder agrees to renovate a kitchen for £12,000. The customer pays a £3,000 cash deposit, an interim payment of £5,000 by bank transfer and a final payment of £4,000 in cash.

The total income is £12,000.

It would not be correct to record only the £5,000 appearing in the bank account. The deposit, stage payments, variations and final payment must be recorded regardless of the payment method.

If the materials cost £4,500, the records must separately show the gross income of £12,000 and the genuine expense of £4,500. It is not correct to declare only the net profit of £7,500 without recording the gross amounts because MTD requires digital records for the business’s income and expenditure. (GOV.UK)

The Relationship Between Private Jobs and CIS

The private customer may be outside CIS, but the main builder may become a CIS contractor when engaging other subcontractors.

For example, a householder pays a main contractor £40,000 for an extension. The householder does not operate CIS. However, if the main contractor separately pays a bricklayer, electrician or roofer for construction work, the relationship between the main contractor and those subcontractors may fall within CIS.

CIS follows the relationship between the person paying for construction work and the subcontractor carrying out the work, not only the identity of the final customer. (GOV.UK)

Therefore, the fact that the ultimate project concerns a private home does not automatically remove the main builder’s CIS obligations towards their team.

Where Can Cash Legally Come From?

The absence of an identical bank withdrawal does not automatically demonstrate that the cash came from undeclared work.

The money may come from a bank withdrawal, cash receipts that have already been recorded, personal savings introduced into the business or a genuine loan.

What matters is that the records show the correct source.

Cash Withdrawn From the Bank

A builder withdraws £1,500 and introduces the amount into petty cash. The builder later pays £1,100 for materials and £200 for waste disposal.

The records should show the transfer of £1,500 from the bank into cash, expenses of £1,300 and a remaining cash balance of £200.

The withdrawal is not an expense. It is simply a transfer of money from one place to another.

Cash Received From Customers

A decorator receives £2,000 in cash for a job and uses £600 to purchase materials.

The correct accounting treatment is:

Business income: £2,000
Materials expense: £600
Cash remaining before other expenses: £1,400

Recording only the £600 invoice without declaring the £2,000 income would result in incorrect records and an incorrect tax return.

Personal Money Introduced Into the Business

An electrician urgently buys £700 of components using personal savings. There is no corresponding £700 bank withdrawal during that period.

This does not automatically make the expense invalid. The amount can be recorded as owner’s funds or capital introduced, while the £700 expense is recorded separately.

However, if such amounts are large, repeated and difficult to reconcile with the person’s genuine financial circumstances, credible explanations and evidence of their source should be retained.

Loan Received

If the cash came from a loan provided by a relative or friend, there should be a contemporaneous agreement recording the date, amount, repayment terms and proof that the money was received.

An explanation invented after an HMRC check has started will have less credibility than documents created at the actual time of the transaction.

The Cash Book Must Balance Mathematically

The cash records must continuously explain how much money existed and how it was used.

The basic formula is:

Opening cash + cash receipts + bank withdrawals + capital introduced + loans received − cash payments − bank deposits − drawings = closing cash

If the accounts contain £20,000 of cash expenses but the recorded sources total only £5,000, there is a difference that must be clarified.

This does not automatically prove fraud. It may mean that owner’s funds, receipts, loans or transfers were omitted. However, a consistently negative or unexplained balance damages the credibility of the records and may lead to questions during a compliance check.

It is not necessary to deposit cash artificially into the bank and then withdraw it again to create apparent “proof”. A deposit shows only that the money entered the account, not whether it came from sales, savings or a loan.

The genuine source must be recorded directly and correctly.

Fabricated or Altered Invoices and Invoices for Non-Existent Transactions

The most serious risk is not the cash payment but the use of a false invoice.

A fabricated invoice may be a document created for materials that were never purchased, an invoice issued in the name of somebody who did not carry out the work, or a genuine document whose amount, date, customer or product description has been altered.

HMRC may classify a situation as a deliberate and concealed inaccuracy where a person deliberately enters an incorrect figure and takes active steps to conceal the error. HMRC guidance expressly mentions the creation of false invoices and the backdating or postdating of documents as examples of concealment. (GOV.UK)

Example: Altered Invoice

A builder buys £480 of materials and receives a genuine invoice. Before sending it to the accountant, the builder alters the PDF and replaces the amount with £1,480.

This is not a simple bookkeeping error. The person knows that the value is false and has changed the document to reduce the taxable profit artificially.

The difference between a mistake and fraud is determined not only by the amount but also by the behaviour. An invoice accidentally imported twice may be an error. An invoice deliberately altered represents a conscious act and can be treated much more severely.

The Same Invoice Used by Relatives or Colleagues

A genuine invoice can be used fraudulently.

Suppose Mihai buys £2,000 of tools and receives the invoice in the name of his business. He later sends a photograph of the invoice to his brother and a colleague.

If all three people each claim £2,000, their returns will contain total expenses of £6,000 for a single genuine purchase of £2,000.

The invoice is genuine, but two of the expenses are false.

Simply possessing a PDF or photograph does not create a right to a deduction. The person must demonstrate that they incurred the cost, received the goods or services and used them in their own business.

A person who deliberately gives false documents or information to somebody else, knowing that they will be used in an incorrect tax return, may also face tax consequences, even if the return was submitted by the other person.

Fundamental Rule

A single genuine transaction cannot create several full expenses for different businesses.

When Can an Invoice Be Shared Legally?

An invoice may be allocated between two or more people where the purchase was genuinely shared, not merely presented that way on paper.

For example, two roofers jointly purchase equipment for £2,000. One pays the supplier, while the other reimburses £1,000 by bank transfer. There is an agreement about ownership, proof of reimbursement and an explanation of the business use.

Each person may consider claiming their genuine £1,000 share, subject to the tax treatment applicable to the equipment.

Neither person can claim the full £2,000.

For a joint purchase, it must be clear who placed the order, who paid the supplier, who reimbursed part of the cost, what goods each person received and how they are being used.

The allocation must not be invented retrospectively solely to reduce profit.

The Same Value Can Legally Appear in Two Sets of Accounts

It is important not to confuse fraudulent duplication of an invoice with two separate commercial transactions.

A subcontractor purchases £1,000 of materials from a builders merchant. The subcontractor performs the work and invoices the main contractor £3,000, consisting of £1,000 for materials and £2,000 for labour.

The subcontractor records:

Income: £3,000
Materials expense: £1,000

The main contractor records the subcontractor’s £3,000 invoice as a subcontractor cost.

There is not automatically any fraudulent duplication. These are two distinct supplies: the merchant supplied the materials to the subcontractor, and the subcontractor supplied labour and materials to the main contractor.

The problem arises if the main contractor also takes the copy of the £1,000 invoice issued to the subcontractor and claims it again as the main contractor’s own direct materials expense, despite not having bought or paid for those materials.

Materials Invoices and the CIS Calculation

The CIS rules allow the contractor to exclude certain costs before calculating the deduction, including materials, but only where the subcontractor paid for them directly.

The contractor can request receipts or other evidence and must verify that the materials amount is genuine. (GOV.UK)

Example

A bricklayer invoices:

Labour: £4,000
Materials: £1,500
Total before VAT: £5,500

If the bricklayer genuinely purchased and paid for the materials, the relevant cost may be excluded before the CIS deduction is applied.

If the materials were purchased by the main contractor, the bricklayer cannot artificially add £1,500 as their own materials merely to reduce the CIS deduction.

Likewise, several subcontractors cannot use the same materials invoice to reduce each of their own amounts subject to CIS.

The invoice must correspond to the subcontractor who genuinely incurred the cost.

Materials Purchased Directly by the Customer

If the private homeowner purchases the materials in their own name and pays the builder only for labour, the builder cannot claim the customer’s invoice as the builder’s own expense.

For example, the customer purchases £4,000 of materials directly and the builder invoices £6,000 for labour. The builder’s accounts contain income of £6,000 and only the expenses genuinely incurred by the builder.

The position is different when the builder purchases the materials and charges the customer a total price.

If the builder purchases £4,000 of materials and issues an invoice for £10,000 covering labour and materials, the builder’s records should normally reflect gross income of £10,000 and a £4,000 expense.

Only the net profit of £6,000 should not be declared as though the other amounts had never existed.

Materials Left Over and Used on Another Job

A builder purchases £2,500 of timber for Job A. At the end, some materials remain and are used on Job B.

The invoice cannot be claimed again for Job B.

The cost was incurred only once. Internal records may allocate materials between projects for profitability analysis, but the total tax expense cannot exceed the genuine amount paid.

Under the cash basis, the cost is generally recognised when it is paid, not each time the materials are moved from one project to another. (GOV.UK)

Tools Purchased From Individuals or Through a Marketplace

A purchase does not automatically become invalid because the seller is a private individual and does not issue a commercial invoice.

A carpenter may buy a second-hand mitre saw for £650 in cash. It would be prudent to obtain a receipt identifying the seller, date, description of the item, model, serial number, price and confirmation of payment.

The original listing, communications, photographs and evidence of use in the business can strengthen the file.

A handwritten document can be credible where it identifies the transaction. However, a note stating only “tools — £2,000”, with no name, date or description, represents very weak evidence.

The larger the amount and the more informal the source, the stronger the secondary documentation should be.

VAT Must Be Considered Separately

Whether a cost is an allowable expense for Income Tax and whether VAT can be recovered are two separate tests.

A cost may be a genuine business expense, but the input VAT may not be recoverable if the invoice is invalid or the supply was not made to the person making the claim.

HMRC’s principle is clear: only the person to whom the supply was made, for use in their own taxable business, can claim input VAT. This principle takes precedence over who physically made the payment or who possesses a copy of the invoice. (GOV.UK)

Therefore, if a VAT invoice is issued to the subcontractor, the main contractor cannot recover input VAT merely because they hold a copy.

Two VAT-registered businesses cannot each recover all the VAT from the same purchase.

A valid VAT invoice is generally required. HMRC may consider alternative evidence in certain circumstances, but acceptance is not automatic. During a check, purchase orders, bank statements, cash books and other records may be examined to confirm that the supply took place, was received by the correct person, was paid for and was used for the business. (GOV.UK)

Fabricated Subcontractor Invoices and “Ghost Workers”

In construction, a separate risk is the fabrication of subcontractor costs.

Problems may include an invoice issued in the name of a relative who did not work, the use of another person’s details, the invention of labour costs, the artificial division of payments between several names or the recording of a fictitious subcontractor.

For a genuine subcontractor relationship, there should be an audit trail: the agreement covering the work, the invoice, proof of payment, CIS verification, the payment and deduction statement and a connection with the relevant project.

A bank transfer proves that money was sent, but does not by itself prove what service was performed. Similarly, an invoice proves that the document exists, not that the work was actually carried out.

In addition, CIS does not replace the employment status assessment. A person does not automatically become self-employed merely because they issue invoices or are paid under CIS.

How Can Problems Arise During an HMRC Check?

MTD quarterly updates do not automatically send every invoice to HMRC. However, during a compliance check, HMRC can request the underlying records and documents and compare the figures with the commercial reality.

Questions may arise where materials costs are disproportionately high compared with turnover, the cash book reaches a negative balance, invoices are in other people’s names, the same invoice number appears repeatedly or the materials declared for CIS exceed the genuine costs.

HMRC may also examine differences between the work carried out, the amounts received, the quantity of materials, the commercial margin and payments to subcontractors.

HMRC acknowledges that a valid VAT invoice is not always sufficient where the remaining evidence does not confirm that the supply was received by the business making the claim. (GOV.UK)

A single unusual item does not automatically demonstrate fraud. However, several discrepancies that support one another can seriously damage the credibility of the records.

What Could the Consequences Be?

If an expense cannot be demonstrated, HMRC may remove it from allowable expenses. The taxable profit may increase, potentially resulting in additional Income Tax and National Insurance, additional VAT where applicable, interest and penalties.

HMRC distinguishes between an error where the person took reasonable care, a careless inaccuracy, a deliberate inaccuracy and a deliberate and concealed inaccuracy.

For domestic inaccuracies, the standard maximum penalties may reach 30% of the potential lost revenue for careless behaviour, 70% for deliberate behaviour and 100% for deliberate and concealed behaviour. The actual percentage depends on the facts, the timing of the disclosure and the taxpayer’s cooperation. (GOV.UK)

Fabricating or altering invoices sits at the most serious end of the spectrum because it involves active steps to support or conceal an incorrect figure.

HMRC also states that the most serious cases may be considered for criminal investigation, even though many cases are initially dealt with through civil procedures. (GOV.UK)

What Happens if the Invoice Was Duplicated by Mistake?

Not every duplication represents fraud.

An invoice may be imported twice through the bank feed, uploaded again by the customer or entered by both the taxpayer and the accountant.

If the error is discovered, the digital record must be corrected as soon as possible. A correction made during the year will be reflected in the next cumulative quarterly update. If the fourth update has already been submitted, the records must be corrected before the tax position is finalised. (GOV.UK)

The essential difference is the behaviour:

A genuine error is discovered and corrected.

An invoice intentionally used by several people is known to be incorrect.

An altered or fabricated invoice involves active steps to create or conceal false information.

Penalties for Quarterly Updates in the First Year

For the 2026–2027 tax year, HMRC will not apply penalty points for late quarterly updates.

However, taxpayers must still maintain digital records and submit all quarterly updates before filing their tax return through MTD.

After the first year, the system becomes points-based. For quarterly obligations, reaching the threshold of four points results in a £200 penalty, followed by additional £200 penalties for subsequent late submissions while the threshold remains reached. (GOV.UK)

This period without penalty points for quarterly updates does not authorise the omission of income or the inclusion of false expenses. Penalties for an inaccurate tax return are a separate matter.

Recommended Procedure for Builders and Tradespeople

A robust system does not need to be complicated. Each project should have a clear code or name, while deposits, stage payments, final payments and variations should be recorded in full, regardless of whether the money entered a business account, a personal account or was received in cash.

For each expense, it should be verified that the invoice genuinely belongs to the business, that the document has not already been used by somebody else and that there is no personal element.

The source of the cash should be identified as petty cash, cash income, a bank withdrawal, owner’s funds or a loan. For materials declared under CIS, it must be verified who purchased them directly, and for VAT it must be confirmed who is the actual recipient of the supply.

The cash account should be reconciled monthly. Regular reconciliation is far safer than trying to reconstruct an entire year a few days before a quarterly deadline or tax return.

Final Checklist for a Cash Payment

Before claiming the expense, check:

1. Did the transaction genuinely take place, and were the goods or services received?

2. Does the invoice belong to the person and business claiming the cost?

3. Does the expense have a clear business purpose, and has the personal element been excluded?

4. Can the payment and source of the cash be explained?

5. Has cash income relating to private jobs been recorded in full?

6. Has the same invoice been used by another person or in another set of accounts?

7. For a shared cost, is each person claiming only the amount genuinely incurred?

8. For CIS, were the materials paid for directly by the subcontractor declaring them?

9. For VAT, is the claim being made by the actual recipient of the supply?

10. Can the digital record and cash account be reconciled with the available documents?

Digital records must be retained for at least five years after the 31 January deadline relating to the relevant tax year. (GOV.UK)

Verdict: Cash Is Not the Main Problem

MTD ITSA does not prohibit cash and does not require every expense to have an identical bank withdrawal.

The absence of a withdrawal does not automatically demonstrate that the money came from undeclared income.

However, an invoice is not an automatic licence to reduce profit.

For every transaction, you should be able to explain:

what you bought, who you bought it from, how much you paid, how you paid, where the money came from, which project the purchase was used for and how it was recorded in the software.

A genuine invoice cannot create full expenses for several relatives, colleagues or businesses. A joint purchase may be divided only according to the cost genuinely incurred and on the basis of clear evidence.

For builders, a distinction must also be made between the private householder, main contractor and subcontractor. A private job remains taxable income even where CIS does not apply, while materials may reduce the amount subject to CIS only where they were paid for directly by the relevant subcontractor.

Golden Rule

Do not artificially create a banking trail and do not use somebody else’s documents. Record the genuine income, the genuine source of the cash, the genuine expense and the person who incurred it.

How DCTaxAgent Can Help

DCTaxAgent can assist sole traders, CIS subcontractors, builders and other tradespeople with checking their MTD ITSA obligations, setting up compatible software, recording private jobs, recording deposits and stage payments, managing cash income and cash expenses, reconciling petty cash, checking materials invoices, separating personal costs, CIS verification, monthly returns, VAT treatment, correcting duplicate invoices, quarterly updates and preparing Self Assessment.

We can also assist with organising documents and rebuilding a clear audit trail where questions arise or HMRC opens a compliance check.

WhatsApp: 07587 532646
Website: www.dctaxagent.co.uk

Disclaimer

This article is intended for general informational and educational purposes.

It does not constitute personalised tax, legal, VAT, CIS or accounting advice.

The tax treatment depends on the nature of the transaction, the accounting method, the identity of the purchaser, the relationship between the parties, the source of the cash, the business use, VAT registration, CIS status and the available documents.

MTD ITSA and Self Assessment apply to eligible individuals. Limited companies have different accounting and tax obligations.

The information reflects official HMRC and GOV.UK guidance available on 4 August 2026.

Recommended SEO Elements

SEO title:
I Paid Cash and Have the Invoice: Is It a Problem for MTD ITSA?

Slug:
cash-payment-invoice-mtd-itsa-builders-duplicate-invoices

Meta description:
Find out when an expense paid in cash is acceptable under MTD ITSA, how private jobs must be declared and the risks of false, altered or repeatedly used invoices.

Keywords:
cash payment MTD ITSA, cash invoice HMRC, private jobs UK builders, duplicate invoices HMRC, false expense invoices, cash jobs UK, CIS subcontractor materials, petty cash builder, sole trader expenses, Making Tax Digital UK.