Sold to the Wrong Customer: Why Late Payment Begins Long Before the Invoice

The invoice is the last act, not the first

When a payment runs past its due date, the instinct is to look at the invoice. Was it sent promptly? Was the purchase order number right? Did it reach the right inbox? These questions matter, and the answers are often embarrassing. But they explain a minority of late payments.

The larger share is decided much earlier, at the point where a business chooses whom to sell to and on what terms. A customer with a history of stretching creditors will stretch you. A customer who was told the work was urgent and the paperwork flexible will treat the paperwork as flexible. A customer who never clearly understood what they were buying will query the invoice, not because they are dishonest, but because the sale left gaps.

The unfashionable conclusion is that late payment is a sales problem wearing a finance costume.

Payment behaviour is a selection criterion

Most UK SMEs screen customers for fit and budget, and stop there. Payment behaviour belongs in the same conversation, not as a moral judgement but as a straightforward commercial variable. A customer who pays in ninety days is not the same customer as one who pays in fourteen, even if the headline value of the order is identical. The difference in working capital requirement can be the difference between a comfortable quarter and a difficult one.

This does not require a credit department. For a small firm, three checks cover most of the ground: whether the company is registered and filing at Companies House, whether its filings suggest stability, and whether anyone in your network has been paid by them before. A trade reference from a supplier is worth more than a bank reference in most SME situations, because suppliers experience the payment behaviour you are trying to predict.

For larger orders, a credit check through a commercial provider is proportionate. For smaller ones, a deposit is often the more elegant solution: it tests commitment and funds the work at the same time.

Terms belong in the sales conversation, not the first invoice

There is a persistent belief that discussing payment terms will sour a deal. In practice, the opposite is closer to the truth. Customers rarely object to clear terms stated early; they object to terms that appear for the first time on an invoice, after delivery, when the negotiating position has already shifted.

State four things before work begins: when the invoice will be raised, what the payment period is, what happens if it runs late, and who in the customer's organisation approves payment. That last point is the most neglected and the most useful. Many delays are not refusals; they are invoices sitting in an inbox belonging to someone who has never heard of you.

Under the Late Payment of Commercial Debts (Interest) Act 1998, UK businesses have a statutory right to claim interest on late payment of commercial debts, along with fixed compensation. The point is rarely to use it. The point is that the entitlement exists and can be referenced calmly when terms are agreed, which changes the tone of the conversation from a favour to a norm.

A one-page customer terms review

Before onboarding any new customer of material size, run the following on a single sheet and keep it with the customer record.

• Company status: registered name, number, filing history reviewed, registered office checked
• Trade reference: one supplier contacted, response noted, date recorded
• Credit check: completed where order value justifies it, result filed
• Deposit rule: percentage or fixed sum required, and the threshold at which it applies
• Invoice timing: trigger event defined, whether on order, on delivery, or on milestone
• Payment period: stated in days, agreed in writing before work starts
• Approver identified: name, role and email of the person who releases payment
• Purchase order position: whether a PO number is required and who supplies it
• Late payment position: statutory entitlement referenced, not threatened
• Walk-away test: the point at which the terms are unacceptable and the answer is no

One page, one decision. The value is not the document; it is that the document forces the conversation to happen before the work does.

The escalation ladder: calm, documented, relational

The other half of the argument concerns what happens when, despite all of this, a payment runs late. The instinct in many small firms is either silence, because confrontation feels costly, or sudden aggression, because frustration has accumulated. Neither works particularly well.

A better approach is a short, predictable ladder. A courteous reminder on the day after the due date, with the invoice attached and a specific question about when payment will be released. A telephone call three working days later, to a named person, noting what was said. A firmer written notice at fourteen days, referencing the agreed terms and asking for a payment date rather than an apology. Beyond that, a decision, made deliberately rather than in frustration, about whether to pause further work.

Each step should be documented, brief and free of editorialising. The tone that protects the relationship is not softness; it is consistency. Customers respond better to a firm process than to a variable mood.

When sales should walk away

This is the part that leaders find hardest, and the part that protects growth most reliably. There are customers whose payment behaviour is not a misunderstanding but a business model, and no amount of process will change it. A customer who refuses a deposit on a first order of significant value, who will not name an approver, who insists on sixty or ninety days without discussion, and who cannot produce a trade reference is telling you something.

Believing them is a strategic decision, not a moral one. The revenue you decline is not the same as the revenue you lose, because the second carries a working capital cost, a management distraction and an opportunity cost against customers who would have paid on time.

What this protects

Growth in a UK SME is usually constrained by cash rather than by demand. Every customer who pays late consumes the working capital that would otherwise fund the next hire, the next piece of equipment or the next quiet month. Treating payment behaviour as part of sales qualification is not an administrative refinement; it is a growth decision dressed in unglamorous clothing.

The firms that scale comfortably tend to be the ones that were boring about this early, long before the pressure made it urgent.