Late payment is one of the most common reasons profitable UK small businesses run into cash-flow trouble. The work is done, the invoice is out, the profit is real on paper — and yet the money that should be paying your own suppliers, your VAT bill and yourself is sitting in someone else's account. Chasing it feels awkward, so most owners leave it far too long, and by the time they act the invoice is weeks overdue and the conversation is ten times harder.
The good news: getting paid on time is mostly a systems problem, not a confrontation problem. Fix the system and you rarely have to have the awkward chat at all.
Set the terms before you start, not after
Half of all late-payment problems are really unclear-terms problems. Agree payment terms in writing before the work starts — on the quote, in the email, on the contract — so 'payment within 14 days' is something the client already signed up to, not something you're springing on them. Put the due date on the invoice itself as an actual date ('due 5 August'), not a vague 'net 14', because a specific date is far harder to ignore.
If you're doing a larger project, stage the payments: a deposit up front, a chunk at the midpoint, the balance on completion. You should almost never be carrying the full cost of a big job on trust.
Invoice immediately, and make it stupidly easy to pay
The single biggest lever most owners never pull: invoice the day the work is done, not at the end of the month. Every day you delay the invoice is a day added to when you get paid. Send it while the job is fresh and the client is happy.
Then remove every excuse not to pay. Include a payment link or your bank details on the invoice itself. Accept the payment method your clients actually want to use. 'I couldn't find your bank details' should never be a reason a payment is late.
A polite reminder sent the day an invoice goes overdue is worth ten strongly-worded emails sent a month later.
Automate the polite chase
This is where most of the awkwardness disappears. Set up automatic reminders: a friendly nudge a few days before the due date, a 'just a heads-up, this is now due' on the day, and a firmer-but-still-polite follow-up if it goes overdue. Most decent accounting software does this for you, so the reminders go out on time whether or not you feel like sending them — which is the whole point, because you never feel like sending them.
Because these are automated and go to every client the same way, nobody takes it personally. It's just how your business runs.
A chase sequence you can actually copy
A workable cadence looks like this: three days before the due date, a friendly note — 'just a heads up, invoice 214 for £480 is due Friday, let me know if you need anything from me.' On the due date itself if unpaid, a short, still-friendly nudge — 'just checking this landed OK, invoice 214 was due today.' At seven days overdue, a firmer written message that states the facts without apology — 'invoice 214 is now a week overdue, please can you confirm when it'll be settled.' At fourteen days overdue, a phone call, not another email — a call is harder to leave unanswered than a message sitting in an inbox. And at 21 to 30 days overdue with no resolution, a final written notice that states plainly you'll be adding statutory interest and reviewing the relationship, followed through on if there's still no response. The exact timings matter less than having a sequence at all, set up once and then simply followed every time, rather than a fresh, awkward decision about what to do next for every overdue invoice.
When it's genuinely overdue
If an invoice sails past its due date despite reminders, pick up the phone. A two-minute call is more effective than another email and usually surfaces the real reason — an admin backlog, a lost invoice, a genuine cash-flow squeeze at their end. Stay calm and specific: 'Invoice 214 was due last Tuesday, can we get that settled this week?'
Know your rights, too. Under the Late Payment of Commercial Debts (Interest) Act, you're generally entitled to charge statutory interest on late business-to-business payments at the Bank of England base rate plus 8%, plus a fixed compensation sum per invoice — £40 for debts under £1,000, £70 for debts between £1,000 and £9,999.99, and £100 for debts of £10,000 or more. You don't need it written into your contract for it to apply; it's implied by law unless your contract already specifies different, equally fair terms. You won't always use it, but knowing it exists changes how you carry yourself in the conversation — mentioning, calmly, that you're 'entitled to add statutory interest and a late payment charge, though I'd rather not have to' does more to move a genuinely reluctant payer than a second polite email ever will.
Fire the persistent offenders
Finally, keep a mental note of who pays late every single time. A client who is consistently 60 days late isn't really a customer — they're an interest-free loan you didn't agree to, funded out of your own cash flow. Run the numbers on a genuinely chronic late payer honestly: a £2,000-a-month client who pays 45 days late every month, without fail, is effectively asking you for an interest-free loan of roughly £3,000 sitting permanently in their account rather than yours — money you could otherwise be using to pay your own suppliers on time, invest in the business, or simply not worry about. Once you see it that way, the choice to either reprice, demand payment upfront, or let the client go stops feeling like losing a customer and starts feeling like closing a loss-making product line. The best clients pay on time and don't make you chase. Aim for a book full of those.
If you don't currently have automated reminders switched on in your accounting software, turn them on today — it's usually a five-minute settings change, and it's the single highest-return five minutes in this whole subject because it runs quietly in the background from then on without you having to remember to do anything. Then pull a list of every invoice currently over 30 days old and, for each one, decide today whether it gets a phone call this week or gets written off as a lesson for next time's payment terms. Leaving it sitting unreviewed is the one option that guarantees nothing improves.
Common questions
How much interest can I charge on a late invoice?
Under the Late Payment of Commercial Debts (Interest) Act 1998 you can charge the Bank of England base rate plus 8% on late business-to-business payments. The base rate is 3.75%, so the statutory rate is 11.75% a year for debts falling late between 1 July and 31 December 2026 — the reference rate is fixed for six months at a time, set on 30 June and 31 December. On top of the interest you can claim a fixed sum per unpaid invoice: £40 for debts under £1,000, £70 from £1,000 to £9,999.99, and £100 for £10,000 or more. On a £5,000 invoice paid 60 days late that is about £97 of interest plus the £70. You do not need any of it written into your contract; it applies by law.
Can I take a client to court over an unpaid invoice?
Yes, and for most small business debts it is more straightforward than owners expect. Claims up to £10,000 in England and Wales go through the small claims track, and you can start one yourself through Money Claim Online without a solicitor. Send a proper letter before claim first, setting out the debt, how it arose and a deadline. Where the debtor is an individual or a sole trader, the Pre-Action Protocol for Debt Claims requires you to allow at least 30 days for a reply and to enclose a reply form and information sheet; against a limited company that protocol does not apply, but a clear letter before claim is still expected. You have six years from the due date, and the court fee is added to your claim.
Will chasing an invoice cost me the client?
Almost never — and the clients it does cost you are the ones you can most afford to lose. What damages a relationship is not the chase but the tone and the timing: an owner who says nothing for six weeks and then sends a furious email because their own VAT bill is due has made it personal in a way an automatic reminder on day one never is. That is the real argument for automating the early stages, because nobody takes a system personally. Most late payments turn out to be administrative anyway — the invoice went to the wrong inbox, the approver was on leave — and a polite prompt gets thanked. A client who walks because you asked to be paid was an unfunded loan, not a customer.
What do I do if a client says they can't pay?
Take it seriously, get it in writing, and stop the bleeding. A client who admits a cash problem is giving you information most late payers never do, and a written payment plan — specific amounts, specific dates, confirmed by email — recovers far more in practice than a stand-off does. Ask for something now rather than everything later, because a part payment today puts it beyond argument that the debt is accepted. Check your contract for a right to suspend work and use it, since continuing to deliver while unpaid turns one bad debt into two. Then check the warning signs: county court judgments against them, a winding-up petition, accounts overdue at Companies House. If those are there, being early beats being patient.
Should I ask for money up front instead?
For anything sizeable, yes, and it is a far better use of your energy than chasing afterwards. A deposit before work starts, a payment at an agreed midpoint and the balance on completion means you are never carrying the whole cost of a job on trust, and it quietly filters out the customers who were never going to pay on time. For a new client with no track record with you, a 50% deposit is unremarkable in plenty of trades and nobody blinks at being asked. For recurring work, a direct debit mandate does the same job more quietly still. The one rule that makes it stick: agree it in writing on the quote before the work starts, so it is a term the client accepted rather than a demand you made later.
