What to do when a major client delays payment: a step-by-step cashflow and invoicing rescue plan

I remember the knot in my stomach the first time a major client missed a payment. It wasn’t just the money — it was the ripple: payroll, supplier invoices, rent, and plans suddenly felt fragile. Over the years I’ve helped many small businesses get through that exact situation. Below is a practical, step-by-step rescue plan you can follow the moment you realise a big client is late paying. These are the actions I actually take with clients — clear, pragmatic and designed to protect your cashflow while preserving the customer relationship where possible.

Immediate triage: check, confirm, and prioritise

Before you panic, do a quick triage. Spend 20–30 minutes and treat this like an emergency fund assessment.

Verify the invoice details: date, amount, VAT, payment terms, invoice number and the correct billing contact.

Check your records: has the payment possibly been received and not reconciled in your accounting software (Xero, QuickBooks, FreeAgent)?

Confirm bank processing times: sometimes a payment has been sent but not yet cleared due to banking delays.

Prioritise your shortfall: list imminent outgoings (payroll, supplier deadlines, rent) and indicate which are non-negotiable.

This gives you a clear picture of urgency and helps you decide how hard to push for immediate payment versus negotiating an instalment plan.

Immediate communication: clear, professional, accountable

Contact the client quickly and calmly. You want to be firm but collaborative — assuming good intent often gets better outcomes than an aggressive tone.

Call first: I usually call the accounts payable contact and the project manager if different. A call gets you faster answers than email.

Follow up in writing: after the call, send a concise email summarising what was discussed and any agreed next steps. This creates a written trail.

Sample chase email I use (paste and adapt):

Hi [Name],

I hope you’re well. Our invoice [#1234] for £[amount], due on [date], appears unpaid on our side. I called earlier and understand there may be a delay. Could you please confirm the expected payment date or any issue preventing payment? If helpful I’m happy to discuss a short payment plan. Thanks, Éloïse

Escalation path: who else to involve

If you get no response within 48 hours, escalate politely but firmly.

Loop in the project sponsor or procurement contact — sometimes the delay is due to internal processing or missing paperwork.

Send a formal payment reminder through your accounting software so it’s logged automatically and includes a clear statement of overdue terms and late payment interest if applicable.

If the client is a larger organisation, use their supplier portal or dispute channels if those exist — many corporates have strict workflows that must be followed to release payment.

Short-term fixes to cover immediate cashflow gaps

While you chase payment, you may need quick access to cash. Here are realistic options and what I recommend depending on your situation.

Option	Speed	Cost/Considerations	When to use
Business overdraft	Fast (if pre-approved)	Interest and fees; suitable for short-term gaps	Small, predictable shortages
Invoice finance / factoring	Fast (days)	Fee on invoice value; reduces admin burden	When multiple invoices are outstanding or you need larger immediate sums
Card/credit	Immediate	High cost if prolonged; useful for suppliers or emergency payroll	Cover small urgent payments
Director loan or shareholder advance	Immediate	Formalise it to avoid tax issues	When owners can temporarily support cashflow

If you’re not already set up with invoice finance or an overdraft, start the application now — these take time. In the meantime, a short director loan documented properly is often the fastest route (but get the paperwork right for tax and accounting).

Negotiation: convert one big headache into an agreed plan

When you reach the client, be prepared to propose realistic solutions rather than only demanding payment. Businesses are more likely to commit to a plan that’s practical for them.

Suggest staged payments: propose dates and amounts so both sides know what to expect.

Offer a small discount for immediate payment if that preserves cashflow and is financially sensible.

Request a purchase order or written confirmation if the late payment was due to missing documentation.

Where appropriate, renegotiate future payment terms to protect you (e.g., move to 30 days from receipt or require deposits).

Always get any revised agreement in writing and saved with the client file. If they promise a direct debit or standing order, ask for confirmation and check your bank after the agreed date.

Protecting yourself legally (when it’s needed)

Legal action is a last resort — it’s time-consuming and can damage relationships — but you should know your options.

Send a formal Letter Before Action (LBA) if the client continues to ignore reminders. This is often enough to prompt payment.

Consider small claims court for sums under the relevant limit in the UK — it’s inexpensive relative to commercial court.

For larger amounts, seek a solicitor’s letter or mediation. I usually recommend trying mediation first as it’s quicker and preserves the relationship better than litigation.

Keep records of all communications, invoices, delivery notes and contracts — these will be crucial if the dispute escalates.

Stabilise your cashflow forecasting and processes after the crisis

Once you’ve resolved the immediate issue, take steps to reduce the risk of recurrence.

Update your cashflow forecast to account for the actual delay and model the impact of similar delays in the future.

Introduce client risk scoring: flag clients with late payment history and alter terms accordingly (deposits, shorter terms, or prepayment).

Automate invoicing and reminder sequences using software (Xero, QuickBooks, or FreeAgent have good automation features). Set up recurring invoices where possible.

Include clear payment terms, late payment interest and a contact escalation path on every invoice and in your contract.

I also recommend a simple credit check for new larger clients — Companies House checks, credit reference sites or even a basic phone call to other suppliers can reveal payment patterns early.

Practical checklist to follow right now

Verify payment in bank and accounting software.

Call client and follow up with the chase email template.

Prioritise imminent outgoings and identify a short-term funding option if needed.

Propose a staged payment plan or discount-for-immediate-payment if appropriate.

Send accounting-software-generated reminders and escalate to a formal Letter Before Action if ignored.

Document any new agreement and update your cashflow forecast.

I’ve seen businesses recover from late payments stronger than before — they come away with better terms, crisper invoicing processes and contingency funding in place. Acting quickly, communicating clearly and having a plan for both the short-term cash gap and longer-term prevention is what makes the difference.