How to Write a Letter Before Action for Unpaid Work
The short answer
A letter before action is your last written demand before court. Say what is owed and why, give a firm deadline (30 days for a homeowner or sole trader, usually 14 for a company), say you will issue a claim if unpaid, and send it so you can prove it arrived.
- Homeowner or sole trader client? Follow the Pre-Action Protocol for Debt Claims: 30 days to reply, with the protocol forms enclosed.
- Company client? 14 days is usual, and you can add statutory interest at 8% over base plus £40, £70 or £100 per invoice.
- Keep it factual. Invoice numbers, dates, the work done, what has been paid. No threats you will not carry out.
- Then claim. Money Claim Online costs from £35; claims up to £10,000 usually go to the small claims track.
You finished the job. The client has had the invoice for weeks. Calls go to voicemail and texts get a thumbs-up and no money. The next step is a letter before action: your final written demand before you go to court.
This guide gives you a letter before action template for unpaid building work, written from the builder's side. It is for UK builders and trades owed money by a homeowner or a business.
If you have not chased properly yet, start with what to do when a client won't pay the final invoice. Owed a lot and want help with the next move? Book a free strategy call.
What a letter before action does
A letter before action is also called a letter before claim. It tells the client what they owe, why, and that you will issue a court claim if they do not pay by a set date.
It matters for two reasons. Many clients pay as soon as the word "court" appears in writing. And if you do go to court, the judge expects you to have warned them properly first. Skip it and you can be penalised on costs, even if you win.
It is not a threat letter. It is a calm, factual record that you gave them every chance to pay.
Who your client is decides the rules
Check who signed the contract before you write a word:
| Client | Deadline to give | What to enclose | Interest you can add |
|---|---|---|---|
| Homeowner or sole trader | 30 days (Pre-Action Protocol for Debt Claims) | Information Sheet, Reply Form and Financial Statement from the protocol, plus the invoice | Only what your contract says; the court may add interest on a claim |
| Limited company, developer or landlord | Usually 14 days | Copy of the invoice and statement of account | 8% over Bank of England base rate plus £40, £70 or £100 per invoice |
The 30-day rule for individuals comes from the court's Pre-Action Protocol for Debt Claims. Send a homeowner a 7-day letter and a judge may pause your claim until you have done it properly.
A business client on a construction contract also gives you the option of adjudication under the Construction Act. That does not cover work on a client's own home. See which payment rules apply to your job.
Owed money and not sure what to send?
Book a free call with our team. We'll look at what you're owed, your paperwork and the fastest route to getting paid.
The letter before action template
Copy this, fill in the brackets, and cut anything that does not apply. Keep it on your company letterhead.
[Your company name, address, phone, email]
[Date]
[Client name and address]
Letter before action: unpaid invoice [number] for work at [site address]
Dear [name],
Under our agreement dated [date], we carried out [short description of the work] at [address]. The work was completed on [date].
We invoiced you £[amount] on [date] (invoice [number]), due by [date]. You have paid £[amount paid]. £[balance] remains unpaid. We wrote to you about this on [dates].
Please pay £[balance] within [30 / 14] days of the date of this letter, by [date], to [bank details].
If you do not pay or reply by then, we intend to issue a court claim for the full amount, plus [statutory interest and compensation under the Late Payment of Commercial Debts (Interest) Act 1998 / interest under our contract] and court costs, without further notice.
If you dispute any part of this amount, please tell us in writing by [date] which part and why, so we can try to resolve it without court.
[For a homeowner or sole trader: We enclose the Information Sheet, Reply Form and Financial Statement required by the Pre-Action Protocol for Debt Claims. Free independent debt advice is available if you need it.]
Yours sincerely,
[Name, position]
Send it by email and by recorded post, and keep both receipts. You want to be able to prove it arrived.
Writing an angry letter. Insults, threats to tell the neighbours or to "take the kitchen back" weaken your case and can be harassment. Facts, figures, dates. Nothing else.
The Cash Flow & Margin Blueprint
Deposits, stage payments and a fill-in payment schedule, so the last invoice is never the big one.
Get the free guideInterest and costs you can add
From a business client, the Late Payment of Commercial Debts Act gives you two extras, unless your contract sets its own fair interest rate:
- Statutory interest: 8% a year over the Bank of England base rate, from the day the invoice became overdue.
- A fixed sum per invoice: £40 for invoices up to £999.99, £70 from £1,000 to £9,999.99, and £100 for £10,000 or more.
Claim one or the other: contract interest or statutory interest, not both.
From a homeowner, you can only add interest if your contract says so. Put a late-payment clause in your terms for every future job.
Not sure what you can claim on top of the invoice?
Book a free strategy call and we'll go through it with you.
If they still don't pay: the next steps
When the deadline passes with no money and no real dispute, you have three routes:
- Money Claim Online. For fixed sums under £100,000. You fill it in on gov.uk, pay the fee, and the court sends the claim to the client.
- Adjudication. Business clients on a construction contract only. An adjudicator decides within 28 days of referral, and the decision is binding for now.
- A solicitor. For large sums, defect counter-claims or a client with assets you will need to chase.
The court fee depends on how much you claim (gov.uk, October 2026):
| Amount you claim | Court fee |
|---|---|
| Up to £300 | £35 |
| £1,500.01 to £3,000 | £115 |
| £3,000.01 to £5,000 | £205 |
| £5,000.01 to £10,000 | £455 |
| £10,000.01 to £200,000 | 5% of the claim |
Claims up to £10,000 usually go to the small claims track, where you do not need a lawyer. If the client ignores the claim, you can ask for judgment by default, then enforce it. A hearing or enforcement adds more fees.
Is it worth it? For a £600 balance, the letter alone usually does the job or tells you it never will. For £6,000, a £455 fee you can add to the claim is a small price.
Make sure it's the last letter you write
A letter before action means the payment terms failed. The real fix is upstream. Take a deposit and stage payments before each stage starts. Get variations signed and paid as you go. Keep the final payment small enough to walk away from.
What this looks like in practice. One BizMentor client, Clayton, signed a £10K job with £5K upfront and staged payments. A late payer can no longer put him at a loss. Individual results, not typical or guaranteed.
Sviat Jay runs Craftex, a London design and build company, and mentors owners one to one himself. He looks at your contracts, deposits and cash, and fixes the weak spot first. He aims for results in about 4 months, not the 1–3 years many coaching programs take.
To set up payment terms that get you paid on time, book a free strategy call. See how much deposit a builder should take and score your cash flow with the free Construction Business Scorecard. If valuations, payment applications and final accounts keep slipping, our commercial management service can run them for you.
Before you send your letter before action
This is general information as of October 2026, not legal advice. For large sums or disputed work, speak to a solicitor.
Before you go
- You know if the client is a homeowner, sole trader or company
- Invoice numbers, dates, payments and balance are correct
- The deadline is 30 days (individual) or 14 days (business)
- Protocol Information Sheet, Reply Form and Financial Statement enclosed for individuals
- Sent by email and recorded post, with proof kept
