The exact ladder for chasing an unpaid invoice in the UK: what to send, when to send it, and when to add statutory interest. Written for small business owners who hate doing this. The whole ladder is on this page; leave your email if you want it as a copy to keep.
Most unpaid invoices are not disputes. They are drift: your invoice sat in an inbox, then everyone moved on. The fix is a ladder you climb on fixed days, where each rung is slightly firmer than the last. You stop deciding whether to chase, because the calendar decides.
| When | What you send | Tone |
|---|---|---|
| Due date −3 days | A short heads-up that the invoice falls due this week, with the invoice attached again | Friendly. You are being helpful, not chasing |
| Day 1 overdue | Polite reminder. Assume cock-up, not conspiracy: "I suspect this slipped through" | Light, no pressure |
| Day 7 | Firm chase. Name the amount, the invoice number and the original due date, and ask for a payment date | Direct and professional |
| Day 14 | Escalation. Mention that statutory interest and compensation apply to late commercial payments, without threatening anyone | Firm, still polite |
| Day 30 | Final notice. State the total including interest, and a 7-day deadline before formal recovery | Formal |
| Day 45+ | Letter before action, then Money Claim Online if it stays unpaid | Legal, by the book |
This is the rung most owners skip, because it feels confrontational. It is not. It is the one that gets most invoices paid.
Subject: Invoice [number], £[amount], now 7 days overdue
Hi [first name],
Following up on invoice [number] for £[amount], which was due on [date] and is now a week overdue. I have attached it again to save you digging.
Could you let me know when payment will be made? If it has already been sent, ignore me and thank you.
If there is a problem with the invoice or with paying right now, tell me and we will sort something out. Silence is the only thing I cannot work with.
Thanks,
[Your name]
If another business pays you late, the Late Payment of Commercial Debts (Interest) Act 1998 gives you the right to charge statutory interest at 8% a year plus the Bank of England base rate, without needing it in your contract. As of August 2026 the base rate is 3.75%, which makes the statutory rate 11.75% a year.
You can also claim a fixed compensation sum per late invoice:
You do not have to charge it. Mentioning that you are entitled to, around day 14, is often enough. The full guide has a worked example of the calculation.
Four questions about one unpaid invoice. Some of them cannot be recovered, and you should know which before you spend another month on it.
Question 1 of 4
Every rung of the ladder, all six templates word for word, the interest worked out, and what to do when they still do not pay. You get the PDF the second you put your email in.
Harness by Heoka watches your accounting software, drafts every rung of this ladder overnight in your tone, and sends from your own email address once you approve it each morning.
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