How to chase an unpaid invoice in the UK

First, rule out the boring explanations.

Most late payments are admin, not malice. Before you chase, check three things: the invoice went to the right person, it shows the correct amount and payment details, and it actually stated a due date. If any of those are wrong, fix and resend with a short apology. You have just found the fastest payment you will collect this month.

Day 1 overdue: the polite reminder.

Chase the day after the due date, not two weeks later. Chasing immediately is not rude. It quietly tells every customer that your invoices do not drift.

Day 7: the firm chase.

Still nothing after a week? Now you name the amount and ask a direct question that needs an answer. The template for this one is in the Late Payment Playbook, word for word. The key line invites them to tell you about any problem, because silence is the only thing you cannot work with.

Day 14: mention statutory interest.

At two weeks overdue, you escalate by telling them what the law already gives you. No threats, just facts.

How statutory interest actually works.

If your customer is another business, the Late Payment of Commercial Debts (Interest) Act 1998 applies even when your contract says nothing about late payment. You are entitled to:

• Interest at 8% a year plus the Bank of England base rate, running from the day the debt became overdue
• Fixed compensation per invoice: £40 for debts under £1,000, £70 from £1,000 to £9,999.99, £100 for £10,000 and over
• Reasonable further recovery costs above the fixed sum

Consumers are different: the Act covers business-to-business debts. For consumer customers, interest depends on your contract terms or the court rate.

Day 30: the final notice.

State the full amount including interest and compensation, and give a specific deadline, normally 7 days, before you begin formal recovery. Keep the tone flat and factual. You are no longer persuading, you are recording.

Day 45: letter before action, then court.

A letter before action is a formal letter stating the debt, the deadline (usually 14 days), and that you will start county court proceedings if it passes. Courts expect you to have sent one, and it is the single most effective email in the whole ladder because it shows you are genuinely prepared to act.

If it still goes unpaid, claims up to £10,000 go through the small claims track, and you can file online with Money Claim Online. Court fees scale with the debt and are added to your claim. Most debts settle before a hearing.

Chasing without burning the relationship.

• Chase the invoice, never the person. "This invoice is overdue" lands better than "you have not paid me".
• Always leave a door open: "if there is a problem with paying right now, tell me and we will sort something out".
• Keep every message short. Long chasing emails read as nervous.
• Move rungs on the calendar, not on your mood. The ladder being automatic is what keeps it polite.

How to stop this happening every month.

The businesses that get paid on time are not luckier. They invoice immediately, take deposits on bigger jobs, put payment terms on the quote rather than the invoice, and chase on a fixed rhythm without fail. The last one is the hardest, because chasing is exactly the kind of awkward, repetitive job that slides when you get busy.

That is the job Harness by Heoka exists to do. It watches your FreeAgent account, drafts every rung of this ladder overnight in your tone, and sends from your own email address once you approve it each morning. Nothing sends without your approval. It is in pilot now, with ten founding places at £10.