Here is how a subcontract got let in Norwich. A developer needed a former nightclub demolished. The demolition firm walked the site and sent over a written quote. Then the two bosses got talking on WhatsApp. Was the job theirs? It was. The price settled at £248,000. Invoices monthly, paid within 28 to 30 days. Somewhere in that thread — no single message, just the run of them — a contract came into existence.
Neither side signed anything. The developer did email over its formal subcontract afterwards, the document with all its standard terms in it — how variations get valued, what happens if the job runs late. The demolition firm never replied to it. They just started work.
Then it went the way these things go. Four invoices landed inside seven weeks. The developer paid £80,000 and dug in on the rest, arguing the invoices didn’t follow the payment rules in its subcontract — the one nobody had ever agreed to.
The court didn’t blink
Last year the argument reached the Technology and Construction Court, the branch of the High Court that handles building disputes. The case is Jaevee Homes v Fincham, and the judge’s finding was plain: “the exchange of WhatsApp messages, whilst informal, evidenced and constituted a concluded contract.” The deal was done in the thread. The formal subcontract, sent after the deal and never agreed, governed nothing. The demolition firm’s award — just under £146,000 — stood.
Two pieces of legal machinery did the damage, and they sit under your jobs too, whether or not you know their names. When a building contract doesn’t spell out how payment works, a set of government fallback rules called the Scheme for Construction Contracts fills the gaps automatically. And if you want to pay less than what’s been asked of you, the law says you must say so in writing, by a deadline, in something called a pay less notice. Miss the deadline and you owe the full amount, fair or not. The developer here missed it — partly because it was working from a rulebook the court later decided had never applied.
A contract is wherever the agreeing happened
The instinct is to read this as a story about WhatsApp. It isn’t. For ordinary commercial deals, English law has never much cared what the agreement is written on. It looks for an offer, an acceptance and a price, and it is entirely relaxed about those arriving as messages tapped out in a van. The court didn’t invent anything new here. It just reminded everyone that casual writing is still writing.
Which means every person in your firm who agrees money by message is forming contracts. The contracts manager who confirms a groundworks price in a thread. The MD who replies “yes mate, crack on” to a quote. Each of those exchanges can be the contract — complete, binding, and containing none of the terms you actually care about. Those terms live in the order that gets sent “when the paperwork catches up”. This case says the paperwork may never catch up. If the deal was already done, the document that arrives afterwards is just a suggestion.
Don’t ban the phones
I know what the tidy-minded response looks like, because I’ve seen firms attempt it. A memo goes out: all commercial agreements must go through the proper channel. It holds for about a fortnight. Site runs on WhatsApp because WhatsApp is fast, and a rule that loses to convenience loses every time. I’d also gently steer you away from the other reflex, which is buying a communications platform with an approvals module. The people doing the agreeing won’t open it.
The fix has to work with the grain. Deals will keep getting struck in threads — fine. What you change is what happens in the ten minutes afterwards. A small tool that lets whoever struck the deal turn it into a one-page confirmed order — scope, price, payment terms, your standard terms attached — and fire it off for a tap-to-accept before anyone mobilises. Thirty seconds, from the same phone the deal was done on. Now the last word in the negotiation is a document you wrote, not a message trail a judge has to reconstruct. Pair it with one habit: anything typed while you’re still haggling carries the words “subject to contract”, a label that tells the law you’re not agreeing yet, only circling.
There’s a second, quieter problem the same tool solves. Those threads are your job’s evidence — who agreed what, when, in whose words — and right now they live on personal phones. When the contracts manager leaves, the record leaves in his pocket. Tie the confirmations to the job, in a system the firm owns, and the evidence stops commuting.
Where this doesn’t apply
Notice who won this case: the informal party. The demolition firm did the work, invoiced, and got paid on the fallback rules — which exist precisely to keep money flowing to people who’ve done work. If your firm is mostly the one being paid, informality mostly cuts in your favour, and I wouldn’t spend money fixing it. The exposure belongs to the paying side — firms letting subcontracts. And if you already have a commercial manager who never lets a start happen before a signed order is out the door, you don’t need a tool. You need to keep paying that person whatever they ask.
But if you place work with subcontractors, and you know deals get struck in threads because you’ve struck some yourself, it’s worth an honest hour working out what a judge would say your last five subcontracts actually were. If you’d like help with that hour — or with the small tool that follows it — get in touch.