Insurance-approved locks in the UK, the full pillar guide.

What "insurance-approved" really means

UK home insurers don’t maintain their own list of approved locks. Instead, every major policy references one or more independent technical standards, and any lock that holds a current certification to that standard is "approved" in policy terms. The two standards that matter on a domestic front door are BS3621 (for mortice locks and lever-operated locks) and TS007 (for Euro cylinders, the cylindrical lock used on UPVC and composite doors). Each is administered by a different body, each is tested differently, and each is identified by a specific physical mark on the lock itself.

A separate accreditation, Sold Secure, runs in parallel and rates locks Bronze, Silver, Gold or Diamond. Sold Secure Gold and Diamond are recognised by most insurers as equivalent to TS007 2-star and 3-star respectively. The Master Locksmiths Association also publishes guidance, but the underlying standards are still BS3621 and TS007.

BS3621, the wooden-door standard

BS3621 is the British Standard that covers thief-resistant locks for final exit doors. The most recent revision is BS3621:2007+A2:2012, which is what new locks are tested against today. Earlier revisions exist (BS3621:1998, BS3621:2004) and most insurers accept any of them on locks fitted before the latest revision.

A BS3621 lock will hold all of the following properties:

• A minimum of five levers (almost always implemented as a 5-lever sashlock or deadlock).
• Anti-pick mechanisms inside the lever stack: false notches and curtain protection.
• Anti-drill protection in the bolt and around the keyway.
• A minimum 20mm bolt throw, hardened to resist saw attacks.
• 1,000-key differs (the number of unique key combinations) as a minimum.
• Resistance to manipulation for a defined minimum time.

The unmistakable mark of a BS3621 lock is the British Standards Institution Kitemark (the heart-shaped logo) engraved or stamped into the brass faceplate of the lock, with the BS3621 reference number alongside. No Kitemark, no compliance, regardless of the brand. Replacing a non-compliant mortice with a Kitemarked BS3621 unit is one of the standard upgrade jobs I quote on the doorstep.

BS8621 and BS10621, the family of related standards

Two related standards apply where BS3621 isn’t suitable. BS8621 covers thief-resistant locks that can be opened from inside without a key (important on flats with fire-escape requirements, where BS3621’s key-both-sides design can be illegal). BS10621 covers locks that are unlockable from outside but bolt-only operable from inside. If you live in a converted block where the front door has to comply with fire regs, the lock you need is BS8621, not BS3621, and most insurers explicitly accept it as an equivalent.

TS007, the Euro cylinder standard

Euro cylinders are the long horizontal lock barrels fitted to UPVC, composite and most aluminium doors. They sit inside a multipoint locking system and operate the gearbox via a cam. They are also the single most attacked component on UK external doors, because of an attack technique called lock snapping.

Lock snapping was developed by burglars in the early 2010s. The attacker grips the protruding portion of the cylinder with a pipe wrench, applies a sharp twisting force, and snaps the cylinder at its weakest internal point: directly across the cam. The two halves come apart, the cam can be operated with a screwdriver, and the multipoint unlocks in under a minute. For about a decade this was responsible for a significant share of UK burglaries on UPVC doors.

TS007 is the standard developed by the Door & Hardware Federation in response. It has three star ratings:

• 1-star (TS007:1): The cylinder alone resists snap, drill, pick and bump attacks for a defined minimum time. 1-star cylinders are designed to be paired with 2-star handles to deliver an overall 3-star solution.
• 2-star (TS007:2): Applied to the door handle furniture, not the cylinder. A 2-star handle physically protects the cylinder from grip with reinforced backplates and security screws. Combine a 1-star cylinder with a 2-star handle and you have a compliant 3-star solution.
• 3-star (TS007:3): The cylinder alone resists every TS007 attack vector (snap, drill, pick, bump, pull). No handle requirement. This is what I fit as standard on every drill job, for a flat £120.

The unmistakable mark of a TS007 3-star cylinder is the BSI Kitemark with three stars stamped on the cylinder body. You can see it by removing the screw on the inside face of the door and pulling the cylinder partway out, or sometimes just by inspecting the visible end of the cylinder under a torch.

Why I always fit 3-star, not 1-star

On paper, a 1-star cylinder + 2-star handle = 3 stars. In practice, the handle gets replaced over the years (cosmetic upgrade, accidental damage, a builder fitting whatever was cheapest), and as soon as the 2-star handle goes, the 1-star cylinder is exposed. A 3-star cylinder doesn’t depend on the handle for its rating, so it survives any future handle replacement. Anti-snap upgrade detail and pricing here.

Sold Secure, the parallel rating

Sold Secure is run by the Master Locksmiths Association and rates locks against burglary attack tools, not just the British Standards methodology. Their scale runs Bronze, Silver, Gold, Diamond. The Diamond rating is broadly equivalent to TS007 3-star and is recognised by all major UK insurers. If your insurer’s policy wording references "Sold Secure Gold" or "Sold Secure Diamond", any cylinder, padlock or chain holding that rating is acceptable.

How to read your own door in five minutes

1. Front door is wooden with a mortice lock? Look at the brass plate on the edge of the door. If you see a Kitemark heart logo with "BS3621" near it, you’re compliant. If you see no Kitemark, no logo, just a bare brass plate, you’re not, even if the lock is mechanically a five-lever.
2. Front door is UPVC or composite with a key-and-handle? The cylinder is what you’re inspecting. Pop the keyhole-side cover off the door if there is one, and look at the visible cylinder face. If you see a Kitemark with one star, the cylinder alone is 1-star and needs a 2-star handle to comply. Three stars, the cylinder is 3-star regardless of handle. No stars, no Kitemark, you have a budget cylinder and lock-snapping is a real risk.
3. Front door has a Yale-type night latch? Yale night latches are not normally insurance-listed on their own; they’re considered an additional security layer rather than the primary lock. Insurers expect a BS3621 mortice to be the main lock on a wooden front door, with the night latch as a secondary. An insurance-rated night latch (BS3621-compliant nightlatch versions exist, look for the Kitemark on the edge plate) does meet some policies.
4. Back door, side door, French doors? These are still "final exit" doors in policy terms. Same standards apply. Conservatory doors are commonly underspecified, and French doors with cheap budget cylinders are a frequent claim point.
5. Accessible ground-floor windows? Most policies require key-operated window locks on accessible windows. There’s no equivalent BS standard widely cited for windows, but the insurer typically just wants "key-operated locks fitted and used".

What insurers actually do at claim time

After a burglary, the insurer instructs a loss adjuster to inspect your home. The loss adjuster checks the front and back doors, photographs the locks, and notes the standard. If the locks don’t meet the policy spec, the claim is paid at a reduced rate or refused outright depending on the policy wording. The phrase to look for in your schedule is the "minimum security warranty" or "endorsement", usually somewhere in the small print referring to BS3621 or "approved 5-lever".

Note that insurers don’t always check at the time you take out the policy. The first time the locks are inspected may well be after a break-in. By then, fixing a non-compliance issue is too late.

Common policy clauses to know

• "Locks fitted at all times of unoccupancy": you must actually use the locks, not just have them fitted. Leaving the deadbolt unthrown when you’re out can void the claim.
• "Approved 5-lever mortice": means BS3621.
• "Minimum 5-lever lock": sometimes a softer wording that accepts non-Kitemarked 5-levers, but always check.
• "Key-operated window locks": must be physically locked when the property is unoccupied or overnight, depending on policy.
• "Anti-snap cylinder" or "TS007 3-star": appearing in newer policies, especially after a previous claim.

What to do if your locks don’t comply

If you’ve checked your front door against the Kitemark guidance above and you don’t see it, you have two routes. Either upgrade now to bring the home into policy compliance, or call your insurer and clarify exactly what the policy requires; they will sometimes accept "five-lever" without the Kitemark, but only with that confirmation in writing.

In practical terms, upgrading is cheap. A BS3621 mortice replacement on a wooden door is a one-hour fitting job. A TS007 3-star Euro cylinder upgrade on a UPVC or composite door is a flat £120 on the doorstep, including the part and a 12-month warranty. Lock replacement service detail.

Specific lock standards I work with

• BS3621:2007+A2:2012: the current revision of the wooden-door mortice standard. Replacement BS3621 5-lever locks fitted on the doorstep.
• BS8621: escape-route equivalent for flats, fitted in place of BS3621 where fire regulations require keyless internal egress.
• TS007 3-star: Euro cylinder anti-snap. Standard fit on every drill job. Manufacturers I carry: ABS, Brisant Ultion, Avocet ABS, Yale Anti-Snap.
• Sold Secure Diamond: equivalent rating, same outcome. Recognised by every major UK insurer.

Related services

• BS Kitemark 3-star anti-snap cylinder upgrade: flat £120, fitted, warrantied.
• Snapped or broken lock replacement: entry plus replacement to insurance spec.
• Tottenham locksmith coverage: area-specific call-out detail for N17.