AnswersWhen a client won't pay
My client keeps promising to pay but never does. What now?
The short answer
Stop collecting promises. If you sold to another business, their promise moves nothing: interest has run since the day after the invoice fell due1, and the £40, £70 or £100 fixed sum3 is owed from that day. What you write back can matter: the late payment law lets interest be cut2 where your own conduct makes that just. So answer each promise in writing with the date and the sum, and send a letter before action after a second missed date, or at 30 days late if sooner.
England and Wales only. WolfX is software, not a law firm.
What you can add
A £5,760 invoice, 57 days late
Say you hired out stage lighting to another business and invoiced £5,760, due on Wednesday 12 August 2026. Their finance team promised it by phone for Friday 4 September, Friday 18 September and Friday 2 October, and nothing came. On Thursday 8 October, 57 days late, they promise Friday 16 October. The invoice went late in the second half of 2026, so interest runs at 11.75% a year: 8% over the Bank Rate5 as it stood on 30 June, which was 3.75%6.
Then it grows by £1.85 a day, about £13 a week, whatever the next promise says. Three dates have passed and it is day 57, past both this page's two-date rule and day 30. So the letter before action goes today, Thursday 8 October, and its 14 days run to Thursday 22 October. Their new date, Friday 16 October, falls inside those 14 days, so they can still keep it. The reply below is for a first or second promise.
The road ahead
Six steps. All free.
Step 1: Reply in writing the day you hear it
Send the letter below. It copies back their date and the amount, asks who approves the payment and which run it is in, and asks for part now. A payment often passes through several departments12, so those are fair questions.
It also names what follows if the date passes. A payment on account tests the promise at once; when part arrives, say so in writing.
Step 2: Leave out "no rush" and "pay when you can"
Interest can be cut where your own conduct makes that just, and conduct covers anything you do or fail to do2. Once the debt exists, the two of you are free to agree new terms for it4, so write nothing that sounds like agreeing to wait.
Put the sum and the daily interest in every email after the first.
Step 3: Offer a written plan if money is tight
If they say cash is the problem, offer a signed plan with dates in place of another open promise: how to set one up. Look at the company's filings first, because a plan only helps if the company is still trading.
Step 4: First date missed? Send one firm email
The next working day after a date passes, check the account. If nothing has arrived, send one firm email with the interest and fixed sum worked out, as in chasing an overdue invoice politely, and ask for a new date in writing.
Step 5: Second date missed? Send the letter before action
The next working day, send a letter before action. A company usually gets 14 days to reply7; a sole trader gets 308.
A new promise after it goes changes nothing; the letter's date stands unless the money lands or a plan is signed. Two is this page's rule, not the law's. Do not let promises carry you past 30 days late, and send it sooner for a sum that hurts.
Step 6: Keep every promise with the invoice
File each promise, note of a call and reply together. A dated promise is a record that they have not said the invoice is wrong.
A written acknowledgment that the money is owed, signed by the person making it11, restarts the six years9 from that day10 if time is still running. The Limitation Act does not say if a typed email name counts, so for an old debt get a signature.
A letter you can copy
Reply to a promise: the date, the sum and what follows
Email it the day they give you a date, whether it came by phone or in writing. Once a second date is missed or the invoice is 30 days late, send the letter before action instead.
Tap a highlighted gap to see what goes in it.
Send it by email the day they give you the date, and keep it with the invoice. If the promise came by phone, this email is your record of it. On a first promise, leave out the paragraph that names the letter before action; it belongs after a missed date. Add nothing like "no problem" or "take your time".
When not to bother
When it isn't worth it
- The first promise was made yesterday. Give it its date and look at the account the day after. A client who has paid on time before may only need that nudge.
- The company shows signs of trouble. Promises count for little when the money is not there. Read the insolvency check before you write again.
- They say the invoice is wrong. That is a dispute, not a promise to pay. Settle what is not in question first: what a dispute changes.
- The sum is small and the client matters. One call and one date confirmed in writing may be all it takes. The steps above are for sums that hurt.
- They are a consumer, or in Scotland or Northern Ireland. The interest rules cover sales between businesses, and the court route here is for England and Wales.
The Wolf's note
A promise is easy to give and easy to let lapse. A date copied back in writing, with the sum beside it, is harder to drop. Decide today what happens if it passes, and the date becomes a check, not a wait.
Mr. Wolf · the AI inside WolfX
What comes next
Your next move
A struggling client wants a payment plan. Should I agree, and how do I set one up?
Yes, with money on signing, a signed written plan and a clause making the whole balance due if a payment is missed.
7 min read · Letter included
My client paid only part of the invoice. What about the rest?
The rest is still owed.
7 min read · Letter included
How do I chase an overdue invoice politely?
Two short emails: on day 7, ask for a payment date; on day 14, name one, with the interest and fixed sum worked out.
5 min read · Letter included
Don't want to do this yourself?
The Wolf does every step for you. He works out the sums, writes the letters and keeps track of every date. Nothing goes without your yes.