What do door and window lock standards actually mean?
They certify that a lock or door has been tested against defined attack methods for a defined time — and they matter practically because insurers specify them, and a policy can be affected by what is fitted.
The standards you will encounter:
BS3621 — the standard for mortice and rim locks on final exit doors. It requires, among other things, that the door cannot be opened from outside or inside without a key once locked, and resists specified attacks. Insurers very commonly require this on wooden external doors, and the phrase in a policy is usually "a five-lever mortice deadlock conforming to BS3621".
The important safety trade-off: a key-operated lock on both sides is a security benefit and an escape risk in a fire, which is why key location matters and why some households should consider this carefully.
TS007 and the three-star system — for euro cylinders on uPVC and composite doors, addressing lock snapping, which became the dominant burglary method for these doors because a standard cylinder can be snapped in seconds with simple tools.
Three stars total is the requirement, achieved either by a 3-star cylinder alone or a 1-star cylinder with 2-star security hardware.
Sold Secure — independent testing with bronze, silver, gold and diamond ratings, used widely for bicycle locks, padlocks and safes, and specified by insurers for higher-value items.
PAS 24 — for complete doorsets and windows tested as assemblies, required for new build and frequently specified in renovation.
Secured by Design — a police-backed scheme certifying products and whole developments.
What actually matters in practice:
Check your insurance policy wording before assuming. Requirements differ, and a claim can be affected by non-compliance.
The weakest point defines the security, and it is frequently a window, a back door, a side gate or an unlocked shed containing tools.
Fitting quality matters as much as the lock, since a good cylinder in a weak door does little.
Visible deterrence — lighting, gravel, a locked gate — prevents more than hardware does.
General information, not insurance advice.