Do I need to send a letter before action before making a court claim?

In practice, yes. Where the debtor is an individual or a sole trader the Pre-Action Protocol for Debt Claims makes it compulsory and prescribes its contents. Where you are a company chasing another company the protocol does not apply, but the general pre-action conduct rules still expect you to set out your claim and give a reasonable chance to respond. A court can penalise you in costs for skipping it.

How long should I give them to respond?

Where the Pre-Action Protocol for Debt Claims applies, 30 days from the date they receive the letter. In a company-to-company debt you have more latitude, and 14 days is normal for a straightforward undisputed invoice. Give longer if the amount is large or the client has asked for time to check something.

Does a letter before action have to come from a solicitor?

No. A letter you write yourself is legally just as effective. A solicitor's letterhead changes the psychology rather than the law, which is sometimes worth the few hundred pounds — and if it is, the reasonable cost is claimable on top of the fixed compensation under the 1998 Act.

What if they respond disputing the debt?

Then you are in a dispute, and the insolvency route closes. Ask for the basis of the dispute in writing, deal with it on its merits, and consider whether the undisputed portion can be paid now while the rest is resolved. A genuine dispute on substantial grounds is a complete answer to a statutory demand.

How to write a letter before action for an unpaid invoice

A letter before action is the formal warning that you are about to sue. It is also, in practice, the message that most often means you do not have to — because it is the first thing in the whole sequence that a client's finance director reads as real.

It is worth taking seriously for two reasons. It works. And if it does not, a judge will eventually read it.

First: who did you invoice?

This decides which rules you are under, and agencies get it wrong constantly.

If the debtor is an individual or a sole trader, the Pre-Action Protocol for Debt Claims applies. It is compulsory, it prescribes what the letter must contain, it requires you to enclose specific documents including an information sheet and a reply form, and it gives the debtor 30 days to respond. Skipping or short-cutting it can cost you in costs later, and can get proceedings stayed while you go back and do it properly.

If you are a limited company chasing another limited company, the protocol does not apply. That surprises people. What still applies is the general Practice Direction on pre-action conduct: set out the claim clearly, enclose the key documents, and give a reasonable time to respond. There is no prescribed form and no prescribed 30 days.

The practical upshot for a typical agency chasing a typical client — company to company — is that you have more freedom, and 14 days is a normal window for an undisputed invoice. But do not import that assumption when you are chasing a freelancer or a sole trader, because there the 30 days is a rule.

What has to be in it

Whichever regime you are in, the letter should contain all of this. In the protocol cases it is mandatory; in company-to-company cases it is simply what makes the letter work.

Who you are, and who you are writing to — the correct legal entity, with its company number if you have it.
What the debt is for, in a sentence a stranger can follow.
Each invoice: number, date, amount, due date, days overdue.
Interest and compensation, itemised — the statutory interest accrued to date and the fixed sum per invoice, with the rate you have used and the basis for it. See how the figure is built.
The total currently claimed, and a note that interest continues to accrue daily.
How to pay, in full detail.
A deadline, as an actual date.
What happens next if it passes — that you will issue proceedings without further notice.
An invitation to raise a dispute or to propose terms, with a route to do it.

Under the protocol there is more: an up-to-date statement of account, the prescribed information sheet, a reply form, and a financial statement form. Those are published with the protocol itself.

The one paragraph people leave out

Invite the dispute. Explicitly.

It feels like weakening your own letter and it is the opposite. Three reasons:

It protects the insolvency route. A debt disputed on substantial grounds cannot found a winding-up petition. If a dispute exists, you need to know now, not after you have paid to issue one.

It reads well. A creditor who asked for the other side's position and got silence is in a much stronger place in front of a judge than one who simply demanded money five times.

It often produces payment. A client who has been sitting on an invoice because of an unraised objection frequently pays the undisputed part the moment somebody gives them a structured way to say what the objection is.

A template

For a company-to-company debt. Adapt it; do not paste it.

Letter before action

[Date]

The Directors [Client Ltd], [registered address]

Dear Sirs,

Outstanding invoices — [Client Ltd] / [Your Agency Ltd]

We write in respect of the following invoices, issued under our agreement of [date] for [one line on the work], which remain unpaid:

Invoice 1041 — issued 14 Jun, due 14 Jul — £8,400.00 — 45 days overdue Invoice 1055 — issued 22 Jun, due 22 Jul — £6,000.00 — 37 days overdue

In addition, and in accordance with the Late Payment of Commercial Debts (Interest) Act 1998, we claim statutory interest accrued to the date of this letter of £[figure], calculated at [rate]% per annum, together with fixed sum compensation of £70.00 per invoice (£140.00). Interest continues to accrue at £[daily figure] per day.

The total currently due is £[total].

We have written to you about these invoices on [dates] and have not received payment or a substantive response.

Please pay the total above by [date, at least 14 days away] to [account details, reference [x]].

If any part of this sum is disputed, please write to us by the same date setting out which invoice is disputed and the basis of the dispute, enclosing any documents you rely on. If you are unable to pay in full, we are willing to discuss a payment schedule, and we would rather do that than litigate.

If we do not receive payment or a substantive response by that date, we will issue proceedings to recover the sum due together with interest and costs, without further notice to you.

Yours faithfully,

[Name], [Position] [Your Agency Ltd]

Sending it properly

Address it to the directors at the registered office, which you can get from Companies House. A letter to your day-to-day contact is a chase. A letter to the registered office is a letter before action.
Send it both ways — post and email — and keep proof of both.
Diary the deadline, and act on it. A letter before action followed by nothing is worse than no letter at all: it is a public demonstration that your deadlines are not real.

Before you send it, spend ten minutes at Companies House

The filing history is free, and it changes what you should do next. Overdue accounts, a newly registered charge, a change of registered office, a resigning director, or a notice in The Gazette all point the same way: move faster, expect less, and take what you can get now rather than the full sum later.

If what you find is a company in trouble, a payment plan accepted this week beats a judgment obtained in four months.

Then what

If the deadline passes with no substantive response, you have a choice between a county court money claim and — for undisputed debts over £750 — a statutory demand and the insolvency route. They are not interchangeable, and picking the wrong one is expensive: how to choose.

General information, not legal advice. Where the Pre-Action Protocol for Debt Claims applies, follow the protocol text itself rather than this summary — the prescribed enclosures are not optional.