The money you're not chasing is already at risk

If you run a specialist subcontracting business in the UK, some of your money is sitting in someone else’s bank account right now, and has been for months.

That’s what retention is. A main contractor holds back a slice of what they owe you, usually around 5%, as security against defects. Half comes back at practical completion. The other half doesn’t come back until the defects liability period ends, typically 12 months later, sometimes 24. By the time it’s due, the job is old news. Nobody on your side is watching for the date. Nobody on their side has any reason to remind you.

That gap is where money quietly disappears.

The numbers are worse than they feel

Government-commissioned research into retention practices (BEIS Research Paper 17, 2017) put the amount held in retention across UK construction at any one time at somewhere between £3.2 billion and £5.9 billion, with a central estimate of £4.5 billion. The same research found that 44% of contractors had lost retention money to insolvency further up the chain, and 71% had experienced delays getting it back at all.

Those aren’t fringe cases. That’s close to half the industry.

Insolvency is the scenario nobody plans for

Retention isn’t ring-fenced. It sits in the main contractor’s general accounts, not in a separate pot with your name on it. If that business goes under before your release date arrives, you don’t get a refund. You get a place in the queue of unsecured creditors, behind the banks and anyone with security over the company’s assets.

Carillion is the case everyone in the industry already knows. When it collapsed in January 2018, it owed roughly £2 billion to its 30,000 suppliers and subcontractors, and estimates of the retention money it was holding at the time ran as high as £1 billion. Firms who had done nothing wrong except win work with the wrong main contractor watched that money vanish into an insolvency process most of them never saw coming.

The warning signs are usually visible before the collapse. Overdue filings, county court judgments, a run of director resignations. They’re on the public record at Companies House the entire time. Almost nobody checks.

There’s a legislative clock running too

The Commercial Payments Bill, introduced to the House of Lords in May 2026, would ban the withholding of retention in construction contracts, impose 8% above the Bank of England base rate as interest on late payment, and fine violators 50% of the amount wrongly withheld. It’s still a Bill, still going through Parliament, and even once passed it carries a transition period before it fully applies. It isn’t law yet and nobody should act as though it is. But it’s a clear signal of where the pressure is heading, and it means overdue retention can already be claimed with statutory interest attached, which most subcontractors don’t currently bother to add.

Why the money usually just sits there

Ask most subcontractor owners why they haven’t chased an overdue retention and the answer is rarely “I forgot.” It’s closer to: I don’t want to be the difficult one. Chase too hard and you risk being left off the next tender list. That instinct is rational. It’s also exactly why so much of this money never comes back. The fix isn’t a sterner letter. It’s not having to send it yourself at all.

Where this leaves you

If you can’t say, right now, how much retention is currently held from you, across how many jobs, with which contractors, and when it’s due, you’re not alone. Almost nobody can answer that without digging through old paperwork. That’s the starting point, not a failing.

Send us your last ten completed jobs and we’ll build that picture for you, free, and show you exactly what’s claimable today. No software to install, no commitment.