How to Write an Overdue Invoice Email Under UK Law (With Templates)

Most overdue invoice emails fail for three specific reasons, and each is fixable. Under the Late Payment of Commercial Debts Act 1998, UK businesses have a legal right to claim 8% above the Bank of England base rate on late B2B invoices — plus fixed debt recovery costs of £40 (under £1,000), £70 (£1,000–£9,999), or £100 (£10,000+). Most UK freelancers never claim this, partly because they don't follow up systematically enough to build a paper trail. According to BACS Payment Schemes, UK businesses are owed £23.4 billion in late B2B payments — and the Atradius Payment Practices Barometer (2024) found 55% of UK B2B invoices experience late payment, making a structured follow-up sequence a financial imperative.

• Too vague. "Just checking in on that invoice" gives the client no information and no clear action. They can file it under "deal with later" indefinitely. Every overdue email needs the invoice number, due date, amount, and a specific ask.
• Too aggressive too soon. Threatening legal action at 7 days overdue damages the relationship and can actually slow payment — clients who feel attacked become defensive. Match your tone to the stage.
• Never sent at all. The most common failure mode. You know you should send a follow-up but you procrastinate because the conversation feels awkward. Having word-for-word templates removes the barrier — you just fill in the details and send.

The fix: a structured 5-stage sequence where each email is slightly more direct than the last. Stages 1–2 assume oversight. Stages 3–4 state consequences. Stage 5 is formal pre-legal notice. See also: how to ask for payment politely for the underlying principles.

The framework below maps to how most overdue invoices actually resolve. Around 60–70% of late invoices are genuinely oversights that resolve at stage 1 or 2. Another 20% need a firm nudge at stage 3. Stages 4 and 5 are for genuinely difficult situations — but having the templates ready means you'll send them instead of procrastinating.

For invoices that reach stage 4 or 5, you may also want to use a formal overdue invoice letter template sent by post or PDF attachment to create a paper trail.

Send this the day after the due date. Assume it was an oversight. Keep it short, warm, and frictionless. Include the invoice number, amount, and a direct payment link if you have one.

Subject: Invoice #[INV-001] — Quick Follow-Up

Hi [Client Name],

I hope you're doing well. I'm just following up on Invoice #[INV-001]
for $[Amount], which was due on [Due Date].

It may have slipped through — no worries if so. You can view and pay
the invoice here: [Payment Link]

If you have any questions about the invoice, I'm happy to help.

Thanks,
[Your Name]

A week in, it's no longer just an oversight. Be direct about the overdue status, restate the amount, and ask for a specific payment date if they can't pay immediately. This is the email that resolves the majority of genuinely late (but not problematic) invoices.

Subject: Invoice #[INV-001] — 7 Days Overdue ($[Amount])

Hi [Client Name],

I wanted to follow up again on Invoice #[INV-001] for $[Amount],
originally due on [Due Date]. As of today, the invoice is 7 days past due.

If payment has already been sent, please disregard this email and let
me know the reference number so I can confirm receipt.

If not, could you let me know when I can expect payment? I'm happy
to arrange a call if there's anything to discuss.

Payment link: [Payment Link]

Thank you,
[Your Name]

Tracking which clients have received which follow-ups is easiest with a dedicated tool. InvoiceGrid logs every chase action so you always know where each invoice stands.

Two weeks is a clear signal that this won't resolve itself. Your tone should be professional but firm. Mention the late fee if your contract includes one. Request a response within a specific timeframe — this creates accountability.

Subject: OVERDUE: Invoice #[INV-001] — $[Amount] — 14 Days Past Due

Hi [Client Name],

This is a follow-up regarding Invoice #[INV-001] for $[Amount], which
is now 14 days overdue (original due date: [Due Date]).

I've reached out twice and haven't received payment or a confirmed
payment date. Please arrange payment by [Date — 5 business days from now]
to avoid any further action.

[If applicable: Per our agreement, a late fee of [X]% applies to invoices
unpaid after [X] days. The current outstanding balance including late fees
is $[Updated Amount].]

Payment can be made here: [Payment Link]

Please reply to this email to confirm your payment date.

Regards,
[Your Name]

This is also a good point to consider a phone call. See invoice follow-up phone call scripts for word-for-word conversation guides.

At 30 days, you're entering formal territory in UK law. This email should reference statutory interest explicitly — under the Late Payment of Commercial Debts Act 1998, you are entitled to claim 8% above base rate from the due date. State the accumulated interest amount. Consider CC'ing the client's accounts payable department or finance team — this often triggers internal action and bypasses the contact who has been ignoring you.

Subject: Final Notice — Invoice #[INV-001] — $[Amount] — 30 Days Overdue

Hi [Client Name],

This is a final notice regarding Invoice #[INV-001] for $[Amount], now
30 days overdue.

Despite my previous emails on [Date 1] and [Date 2], I have not received
payment or a satisfactory response.

If I do not receive full payment or a confirmed payment arrangement by
[Date — 5 business days from now], I will have no option but to:
  - Refer this matter to a collections agency, and/or
  - Pursue recovery through the appropriate legal channels

I would strongly prefer to resolve this directly. Please contact me
immediately to arrange payment.

Outstanding balance: $[Amount]
Payment link: [Payment Link]
My phone: [Your Phone Number]

Yours,
[Your Name]
[Your Business Name]

This email pairs well with a formal final notice invoice email sent as a PDF attachment for documentation purposes.

At 60+ days, you've exhausted normal follow-up. For UK businesses, the next step is Money Claim Online (MCOL) — the UK government's online court filing service for debts up to £100,000. Filing costs £35–£455 depending on the claim amount and are recoverable if you win. This email is your formal pre-MCOL notice. Keep a copy — it is your evidence that you gave the client fair warning.

Subject: Pre-Legal Notice — Invoice #[INV-001] — $[Amount] — [Your Business Name]

Dear [Client Name],

I am writing regarding Invoice #[INV-001] issued on [Issue Date] for
$[Amount], now [X] days overdue. Despite multiple written and verbal
follow-ups, this invoice remains unpaid.

I am formally notifying you that if payment in full is not received
by [Date — 7 calendar days from today], I will proceed with:

  1. Filing a claim in [small claims court / civil court, as applicable]
  2. Referring the debt to [collections agency name, if applicable]
  3. Reporting the outstanding debt to relevant credit reporting bodies

For the record, previous contact dates were:
  - [Date of Email 1]
  - [Date of Email 2]
  - [Date of Email 3]
  - [Date of Phone Call, if applicable]

Payment can be made via [payment method] to [payment details].

This email constitutes formal written notice.

[Your Full Name]
[Your Business Name]
[Your Address]
[Your Phone]

Before sending this email, review your original contract and the payment terms you agreed to. If the amount justifies it, consult a solicitor or attorney for jurisdiction-specific advice.