What locks do home insurers actually require?

Why it matters

Home insurance policies commonly include a security condition. If a burglar forces a door that didn't have the specified lock, the insurer can reduce or refuse the claim. The requirement is often written in language most people skim past: "five-lever mortice deadlock conforming to BS3621", "key-operated locks on all accessible windows", "anti-snap cylinders". Below is what each of those means in practice.

Timber front and back doors: BS3621

The standard insurers ask for on wooden doors is BS3621. Look at the faceplate of the lock on the edge of the door: a compliant lock has the Kitemark and "BS3621" stamped on it. A "5-lever" lock that doesn't carry the Kitemark is not the same thing, and older locks marked BS3621:1980 are usually accepted but are worth upgrading when they wear.

Two related standards catch people out. BS8621 is the version for doors that must open from the inside without a key (flat entrance doors on a fire escape route, for example). BS10621 is for doors that lock from the outside only. If you live in a flat, your insurer or freeholder may specify one of these instead.

uPVC and composite doors: anti-snap cylinders

The weak point on most plastic and composite doors is the euro cylinder — the barrel the key goes into. A standard cylinder can be snapped with basic tools in seconds, and it has been the most common method of entry in the south of England for years. Insurers increasingly specify TS007 3-star cylinders, or the equivalent Sold Secure Diamond (SS312). The rating is a reliable guide: either fit a 3-star cylinder, or a 1-star cylinder with a 2-star security handle, which together add up to the same protection.

A 3-star cylinder costs a little more than a basic one but takes minutes to fit and needs no change to the door or the multipoint mechanism. It is the single best value security upgrade on a uPVC door.

Windows

Policies usually say "key-operated locks on all accessible windows". "Accessible" means ground floor and anything reachable from a flat roof, porch, wheelie bin or drainpipe. On uPVC windows the handle itself is normally lockable — look for a small key slot on the handle. On older timber windows, surface-mounted key-locking window locks meet the requirement and are cheap to fit.

Patio, French and bi-fold doors

Sliding patio doors need an anti-lift device and a key-operated lock; French doors need shoot bolts top and bottom on the second leaf plus a proper lock on the first. Modern bi-folds normally comply as supplied, but the cylinder is often a basic one and worth swapping for a 3-star.

How to check your own house

• Front and back door edges: is "BS3621" stamped on the lock faceplate?
• uPVC/composite doors: does the cylinder show a 3-star or Diamond mark on its face, or does the handle carry a 2-star mark?
• Ground floor and reachable windows: does every handle lock with a key?
• Patio doors: is there a lock beyond the latch, and a block or bolt stopping the door being lifted out?
• Then read the security section of your policy schedule and compare.

What it costs to put right

For most Basingstoke houses, bringing every door up to the common insurer wording is a single visit: a BS3621 lock on a timber door, a 3-star cylinder on each uPVC door, and locking handles on any windows that need them. We quote a fixed price before we start and fit insurance-rated products from stock on the van. If you'd like us to check first, a security survey is free and comes with a written list.

Questions we're often asked