How to spot cashflow pressure before it becomes a crisis

Most UK SME cashflow crises are visible 60-90 days before they hit. The signs are clear, the maths is straightforward, and the fixes are usually available — if the owner sees them in time. The businesses that fail are almost never the ones that misjudged a decision. They are the ones that did not see the problem until the bank bounced a payment.

This is a practical checklist of the earliest warning signs of cashflow pressure — and what to do about each one while there is still room to act.

Warning sign 1: Debtor days are creeping up

Debtor days = (trade receivables ÷ revenue) × 365. It measures how long, on average, it takes customers to pay you.

If the number was 35 days six months ago and it is 42 days now, something is wrong. Either a customer has slowed, or your chase discipline has slipped, or more invoices are falling into disputes.

A 7-day drift on £600k annual revenue is £11,500 of cash that used to be in your bank and now is not. That is not a disaster on its own — but it is a leading indicator.

Action: pull an aged-debtor report today. Every invoice more than 14 days overdue gets chased by phone this week. Not email — phone. Most overdue invoices clear within 3 days of a polite phone call.

Warning sign 2: Stock is building up

For product businesses: stock days = (inventory ÷ COGS) × 365. Rising stock days means you are buying faster than you are selling.

Some stock build is deliberate (seasonal preparation, new product launch, bulk-buy savings). The dangerous kind is accidental — when sell-through has slowed but purchase orders are still flowing at the old rate.

Action: compare stock days month-on-month. If the number is up 15%+ without a deliberate reason, pause non-critical purchase orders and review fast-moving vs slow-moving SKU mix.

Warning sign 3: Creditor days are creeping up

The mirror image: creditor days = (trade payables ÷ COGS) × 365. Rising creditor days means you are paying your suppliers slower.

Some of this is smart working capital management. But uncontrolled drift is a sign of cash pressure — the business is short on cash, so it is quietly extending supplier payment without telling anyone. This usually ends badly, because key suppliers notice before you think they do.

Action: if creditor days are drifting up beyond normal terms, have the conversation with priority suppliers proactively. A negotiated extension is a commercial relationship. A unilateral one is a reputation problem.

Warning sign 4: Your VAT and PAYE pot is thinner than it should be

Every VAT-registered UK business builds up a VAT liability monthly. Every employer builds up a PAYE/NIC liability monthly. These are not your money — they are HMRC's, you just hold them temporarily.

A business with healthy cashflow has a VAT and PAYE reserve set aside that covers the upcoming liability. A business with cashflow pressure starts dipping into that reserve to cover operational costs.

Test: at month-end, do you have separate cash set aside for the next VAT and PAYE payment? If no, you are not in a crisis — but you are vulnerable to one. The next bad month and you won't have the cash for the tax payment either.

Action: move VAT and PAYE reserves to a separate sub-account that you do not touch. Treat it like any other restricted cash. This one change protects more UK SMEs from HMRC enforcement than any other piece of advice in this article.

Warning sign 5: Your 12-week cashflow forecast looks optimistic

Every UK SME should have a rolling 12-week cashflow forecast. Most do not. Of the ones that do, most build in the optimistic case — assumed receipts that won't arrive on time, revenue assumptions that are aspirational.

A realistic 12-week forecast includes:

• Receipts at actual debtor-days (not on the invoice due date)
• All known outgoings (rent, wages, VAT, PAYE, supplier invoices, direct debits)
• Buffer for unplanned costs (at minimum 5% of expected outgoings)
• Clear call-out of the lowest cash point in the 12-week horizon

Action: if your lowest projected cash point in 12 weeks is less than 2 weeks of outgoings, you have a pressure situation now — even if the current balance looks fine. Cash pressure is always future-dated.

Warning sign 6: You are declining business because of cash, not margin

When a business turns down a good-margin order because it cannot fund the working capital (materials, labour, stock) to deliver it, that is the clearest sign of cashflow pressure — and also one of the most expensive.

Each turned-down job is foregone margin. Enough of them in sequence and the business shrinks.

Action: this is the moment to have the bank conversation. An overdraft or invoice finance facility, arranged when the business is healthy, costs less and is easier to secure than one arranged when it is not. The UK SME lending market is tightening (see our daily briefing) — get the facility in place before you need it.

Warning sign 7: You have stopped looking at the numbers weekly

The most reliable early indicator of a cashflow crisis is not a number at all — it is a behaviour. Owners under cashflow pressure tend to look at their numbers LESS, not more, because the numbers have become unpleasant.

If you are avoiding your own reports, that is the warning sign that the warning signs are being missed.

Action: book a 30-minute weekly review with yourself, same time every week, non-negotiable. Review aged debtors, bank balance, 4-week cash projection, and margin by major product or service. If you cannot face it alone, do it with a trusted advisor, accountant, or your LumixAI dashboard.

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