When a client refuses to pay an invoice, it creates an immediate problem that goes beyond money. You have already done the work. You have delivered the service or supplied the goods. And now the person who agreed to pay for it is either ignoring your emails, disputing the amount, or simply refusing to honour the agreement. For a small business, even a single unpaid invoice can disrupt cash flow, delay wages, and create genuine financial stress.

The good news is that UK law gives you clear rights when it comes to unpaid commercial debts. You do not need a solicitor to start the process. You do not need to accept silence. And you do not need to write off the money unless you choose to. This guide walks you through every step — from the first follow-up through to court action — so you know exactly what to do, in what order, and when to escalate.

Before You Escalate: Rule Out Simple Problems First

Not every unpaid invoice is a refusal to pay. Before you treat the situation as a dispute, check whether the non-payment has a simpler explanation.

Was the invoice sent to the right person? In larger companies, invoices sometimes sit with the wrong contact. Confirm you have the correct accounts payable or finance email address.
Was the invoice received at all? Emails get filtered, lost, or overlooked. Resend the invoice and ask for confirmation of receipt.
Are the payment details correct? A wrong sort code, missing reference, or outdated bank details can delay payment even when the client fully intends to pay.
Is there a genuine dispute about the work? If the client believes the work was incomplete, late, or not as agreed, they may be withholding payment deliberately until the issue is resolved. That is a different situation from outright refusal.

Ruling out these causes first protects the relationship and saves you from escalating unnecessarily. If the invoice really has been received, the work really was completed, and the client is simply not paying — then it is time to follow the formal process.

Fintech infographic showing legal steps for small business invoice debt recovery

Step 1: Send a Firm Payment Reminder

Your first formal step is a clear, professional payment reminder. This is not a casual nudge. It is a structured message that states the facts and sets a deadline.

Your reminder should include the invoice number and date, the amount owed, the original payment terms and due date, a clear statement that the invoice is now overdue, a new deadline for payment (typically 7 days from the date of this reminder), and your bank details so the client has no excuse for not knowing where to send the money.

Keep the tone professional but direct. You are not apologising. You are not asking for a favour. You are stating a fact — the invoice is overdue — and setting a deadline for resolution.

If the client responds and offers a reasonable explanation or payment plan, you can decide whether to accept it. If they ignore this reminder entirely, move to the next step.

Step 2: Add Statutory Interest and Compensation

Most UK small business owners do not realise they have an automatic legal right to charge interest and compensation on overdue commercial invoices. You do not need to have included this right in your contract. It exists by law.

What the law says

The Late Payment of Commercial Debts (Interest) Act 1998 gives any UK business the right to charge statutory interest on late business-to-business payments. The rate is 8% above the Bank of England base rate. You cannot claim statutory interest if your contract already specifies a different interest rate that qualifies as a substantial remedy.

Statutory compensation

On top of interest, you can also claim a fixed compensation amount based on the size of the debt:

Debt Amount	Fixed Compensation
Up to £999.99	£40
£1,000 to £9,999.99	£70
£10,000 or more	£100

How to apply it

You do not need the client's permission to add statutory interest. Calculate the interest from the day after the payment was due, apply the 8% plus base rate formula, add the fixed compensation, and include the updated total in your next communication to the client.

Adding statutory interest serves two purposes. First, it increases the amount the client owes, which creates a financial incentive for them to pay quickly. Second, it demonstrates that you know your legal rights, which signals that you are serious about recovering the debt.

Step 3: Send a Letter Before Action

If the payment reminder and the addition of statutory interest have not prompted payment, the next step is a formal Letter Before Action. This is a legal pre-court document that puts the debtor on notice that you intend to begin legal proceedings if the debt is not settled.

What it should contain

Your business name and the client's business name
The invoice number, date, and original amount
The total now owed including statutory interest and compensation
A summary of the work or service provided
A statement that the debt remains unpaid despite previous reminders
A clear deadline to pay — 14 days is the standard period used in most letters before action
A statement that if payment is not received within the deadline, you will commence court proceedings without further notice

Why it works

A Letter Before Action is not a legal requirement before filing a court claim, but it is expected under the Pre-Action Protocol for Debt Claims. Courts look favourably on claimants who followed the protocol, and unfavourably on those who rushed to court without giving the debtor a fair opportunity to pay. It also carries real psychological weight. Most businesses that have ignored informal reminders take a Letter Before Action seriously because it signals that litigation is genuinely about to begin.

In many cases, the Letter Before Action alone resolves the matter. The client pays because the cost and disruption of defending a court claim is far greater than settling the invoice. If they still do not pay after receiving the letter, you now have a clear paper trail showing you acted reasonably at every stage.

Step 4: File a Claim Through Small Claims Court

If the Letter Before Action does not produce payment within the deadline, your next option is to file a formal claim with the court. For debts up to £10,000, this is handled through the Small Claims Track of the County Court, which is designed to be accessible without a solicitor.

How to file

The simplest method is through Money Claim Online, which is the government's digital portal for issuing county court claims. You complete a claim form with your details, the debtor's details, the amount owed including interest and compensation, and a brief summary of why the money is owed. You pay a court fee, which varies based on the claim amount:

Claim Amount	Court Fee
Up to £300	£35
£300.01 to £500	£50
£500.01 to £1,000	£70
£1,000.01 to £1,500	£80
£1,500.01 to £3,000	£115
£3,000.01 to £5,000	£205
£5,000.01 to £10,000	£455

What happens after you file

The court issues your claim and serves it on the debtor, who then has 14 to 28 days to respond. They can pay the full amount and the matter is closed. They can dispute the claim, in which case they must file a defence. Or they can ignore it entirely, in which case you can apply for a default judgment — meaning the court rules in your favour without a hearing because the debtor did not respond.

UK business owner reviewing unpaid invoices on accounting dashboard

Most small claims for unpaid invoices never reach a hearing. The act of receiving a formal court claim is usually enough to prompt payment, because the debtor now faces a County Court Judgment on their credit record if they lose or fail to respond.

Step 5: Consider a Statutory Demand

If the debt exceeds £750 and you believe the client has the ability to pay but is deliberately refusing, you have an additional option: issuing a statutory demand under the Insolvency Act 1986.

A statutory demand is a formal written demand that gives the debtor 21 days to pay. If they fail to pay within that period, you can apply to the court to begin insolvency proceedings — bankruptcy if the debtor is an individual, or a winding-up petition if the debtor is a company.

This is a serious escalation. It should not be used as a routine debt collection tool, and it should not be used if the debt is genuinely disputed. But for clear-cut cases where a company owes you money and is simply refusing to pay, the threat of a winding-up petition is often the single most effective lever available. Company directors take winding-up petitions extremely seriously because they can force the closure of the business.

Step 6: Use a Debt Recovery Service

If managing the process yourself is taking too much time or if the debt is complex, you can outsource to a professional debt recovery service. These range from commercial debt collection agencies to solicitors specialising in B2B debt recovery.

How they work

Most debt recovery agents operate on either a fixed fee or a percentage of the recovered amount, typically between 5% and 15%. They handle the communication, escalation, and if necessary, the legal proceedings on your behalf. The advantage is that they do this every day and know how to apply the right pressure at the right time.

When to use one

Debt recovery services are most useful when you have multiple unpaid invoices across different clients, when the amounts are large enough to justify the fee, when the debtor is deliberately evasive or difficult to contact, or when you simply do not have the time to manage the process alongside running your business.

How to Protect Yourself Before the Problem Starts

The best debt recovery strategy is the one you never have to use. While you cannot control whether a client decides to pay, you can build a process that makes non-payment harder for them and easier for you to pursue.

Use written contracts or terms of business. Every engagement should have clear payment terms agreed before work begins. Include the payment deadline, the consequences of late payment, and a reference to your right to charge statutory interest.
Invoice promptly and professionally. Send the invoice as soon as the work is delivered or the milestone is reached. Include all required details — your business name, the client's name, the invoice number, the amount, the due date, and your payment details.
Set clear payment terms. Net 14 or Net 30 are standard, but whatever you choose, make sure it is stated on every invoice and agreed in advance.
Use automated payment reminders. Do not rely on memory. Use your accounting software to send reminders automatically before and after the due date.
Request deposits or staged payments for larger projects. Taking a 25% to 50% deposit before starting work reduces your exposure if the client stops paying partway through.
Track your invoices properly. Maintain a clear record of every invoice, its status, when reminders were sent, and any communication with the client. If you ever need to take legal action, this documentation trail is your evidence.

Why Documentation Matters More Than Anything

Every step in this process — from the first reminder email to the Letter Before Action to the court claim — depends on having clear records. You need to show what was agreed, what was delivered, when the invoice was sent, when it was due, and what follow-up actions you took.

This is where your accounting software becomes a legal tool, not just a bookkeeping tool. If your invoicing platform tracks when invoices were sent, when they were viewed, when reminders were issued, and how long they have been overdue, you have a ready-made evidence file. Ageing reports that show the debt's timeline, payment history per client, and a full audit trail of communications make the process of escalating to a Letter Before Action or court claim significantly faster and stronger.

Without good records, you are relying on memory and scattered emails. With good records, you walk into every stage of the process with clear, timestamped evidence that supports your position.

The Full Escalation Timeline

Here is the complete sequence from overdue invoice to final resolution, with typical timeframes for each stage.

Stage	Action	Typical Timeframe
1	Firm payment reminder with 7-day deadline	Day 1 after due date
2	Add statutory interest and compensation	Day 8
3	Send Letter Before Action with 14-day deadline	Day 14
4	File claim through Money Claim Online	Day 28
5	Court serves claim; debtor has 14–28 days to respond	Day 28–56
6	Default judgment if no response, or hearing if disputed	Day 56–90

Most cases resolve at Stage 1 or Stage 3. Very few reach a court hearing. The process is designed to give the debtor multiple chances to pay before legal consequences apply, which is why courts expect you to follow this sequence rather than jumping straight to litigation.

This article is for informational purposes only and does not constitute legal advice. For guidance specific to your circumstances, consult a qualified solicitor or debt recovery professional.