Guide
Insurance Approved Locks: BS 3621, TS 007 and More
Home insurers usually ask for a BS 3621 mortice deadlock or nightlatch on timber exit doors, and a multipoint lock with a TS 007 3 star or SS 312 Diamond cylinder on uPVC and composite doors. Wording varies by policy, so read yours. An anti-snap cylinder costs about £137 to £150 fitted, from the MLA and Checkatrade.
What does 'insurance approved lock' mean?
There is no single 'insurance approved' standard. The phrase usually means a lock that meets the British Standard or Kitemark your home insurance policy names. Insurers write their own wording, and it differs between policies, so the policy document is the only reliable answer for your home.
The pattern across many policies is:
- Timber front and back doors: a 5-lever mortice deadlock to BS 3621. - uPVC and composite doors: a multipoint lock with a cylinder rated TS 007 3 star or SS 312 Diamond.
That pattern is consistent across locksmith guides, but it has not been checked policy by policy. If your locks do not meet your policy's wording, a claim after a burglary can be reduced or refused.
What is BS 3621, and what about BS 8621 and BS 10621?
BS 3621 is the British Standard for thief-resistant key-locked locks. On a timber door it is usually a 5-lever mortice deadlock, and it also covers some nightlatches. Look for the Kitemark and 'BS 3621' stamped on the faceplate, the metal plate on the edge of the door.
Two related standards cover locks that can be opened from inside without a key:
- BS 8621: keyless exit from inside, typically with a thumb-turn. It is often used in flats. - BS 10621: a dual-mode lock that suits some flats. It is not intended for homes with a single exit.
If you live in a flat or a house with only one exit door, ask the locksmith which of these fits your building, and check your policy accepts it.
What do TS 007 stars and SS 312 Diamond mean?
Both rate euro cylinders, the barrel-shaped lock on most uPVC and composite doors, which burglars attack by snapping.
- TS 007 is BSI's Kitemark scheme for cylinders and door handles. Security comes from stars: a 3 star cylinder on its own, or a 1 star cylinder with a 2 star handle, gives the anti-snap rating. - SS 312 Diamond is Sold Secure's top grade for cylinders. Sold Secure certifies products, not the people who fit them.
The markings are on the cylinder's face. A cylinder without them may still lock, but it has not passed the test. An anti-snap cylinder costs about £137 to £150 fitted: the MLA's 2026 list starts at £137, with parts from £64, and Checkatrade gives an average of £150.
What is PAS 24?
PAS 24 is a security test for a whole doorset or window, not just the lock. It covers the frame, hinges, glazing and hardware together. It is the baseline for Secured by Design's Police Preferred Specification, the police-backed product accreditation.
You usually meet PAS 24 when buying a new door or window. A locksmith can fit a TS 007 or BS 3621 lock to an existing door, but cannot make a door PAS 24 by changing the lock, because the test is of the whole unit.
What does it cost to bring your locks up to standard?
From the published price guides:
| Job | Typical price | Sources | |---|---|---| | Anti-snap cylinder, fitted | £137 to £150 | MLA, Checkatrade | | Mortice deadlock (BS 3621), fitted | £100 to £205 | MLA, Checkatrade, MyJobQuote, Bark | | Euro cylinder change, fitted | £105 to £175 | MLA, MyJobQuote |
Ask the locksmith to write the standard on the invoice, for example 'TS 007 3 star cylinder fitted'. That invoice is the evidence your insurer will ask for after a claim.
If only one door falls short, fix that one first; there is no need to replace locks that already meet your policy. Several locks on one visit usually cost less each, because the travel is paid once. Ask for a price per lock and a total, and whether VAT is included.
Common questions
Do I need BS 3621 locks for my home insurance?
Many policies ask for a BS 3621 mortice deadlock on timber exit doors, but wording varies. Read your policy, or ask your insurer, for the exact standard and which doors it applies to.
How do I tell if my cylinder is anti-snap?
Look at the face of the cylinder for the Kitemark with 3 stars (TS 007) or the Sold Secure Diamond mark (SS 312). If there is no marking, ask a locksmith to check it.
Are uPVC door locks covered by BS 3621?
BS 3621 is mainly for mortice deadlocks and nightlatches on timber doors. On uPVC and composite doors, insurers usually look at the cylinder rating instead: TS 007 3 star or SS 312 Diamond.
Should I keep the invoice for new locks?
Yes. An invoice naming the standard fitted, such as TS 007 3 star or BS 3621, is the evidence an insurer asks for after a claim. Keep it with the policy.