Almost every UK home insurance policy includes a security clause. It usually appears deep in the policy schedule, in language designed to be skipped. But it imposes contractual obligations on what locks are fitted to your home, and getting it wrong is one of the most common reasons home insurance claims are reduced or refused.
The two specifications that matter
For most UK homes, only two lock standards genuinely matter: BS3621 for wooden doors with mortice locks, and TS007 for UPVC and composite doors with Euro cylinder multipoint mechanisms. If your front and back doors meet whichever standard applies, you have complied with virtually every standard UK home policy.
BS3621 - for wooden doors
BS3621 is the British Standard for thief-resistant mortice deadlocks - the chunky lock that drops a square steel bolt sideways into the door frame when you turn the key. To meet BS3621, a mortice deadlock must have at least 5 levers, a 20mm bolt throw, hardened anti-saw inserts in the bolt, and a kitemarked faceplate. The current standard is BS3621:2007.
You can identify a compliant lock by opening the door and looking at the faceplate on the edge of the door. A genuine BS3621 lock has the BSI kitemark (a heart-shaped logo) plus "BS3621" plus the year embossed or laser-etched into the metal. Generic locks, even ones marked simply "5 lever", do not meet the standard.
TS007 - for UPVC and composite doors
UPVC and composite doors don't use mortice locks - they use a multipoint mechanism driven by a Euro cylinder, and the security weakness has historically been the cylinder itself, not the multipoint. Lock-snapping (where a burglar snaps the cylinder in half with mole grips) was the dominant entry method on UPVC doors through the 2010s.
TS007 is the UK standard developed specifically to resist lock-snapping, tested by Sold Secure or the Door and Hardware Federation:
- 1-star cylinder - basic anti-snap protection. Must be paired with 2-star door furniture (handles, escutcheons) to give equivalent protection.
- 2-star cylinder - intermediate. Rare in practice; insurers usually accept 1-star + 2-star furniture or 3-star alone.
- 3-star cylinder - full anti-snap protection in the cylinder alone, no special door furniture required.
Sold Secure also publishes its own "Diamond" grade for UPVC cylinders, which is roughly equivalent to TS007 3-star plus enhanced protection against picking, drilling and bumping. Some high-value home policies require Sold Secure Diamond.
What your policy probably says
The specific wording varies by insurer, but the pattern is consistent. Look in your policy schedule for a section titled "Security" or "Endorsements" or similar. You'll find phrases like:
- "All final exit doors must be fitted with a 5-lever mortice deadlock to BS3621 or a multipoint locking system with a TS007 3-star cylinder"
- "All keys must be removed from internal locks when the property is left unattended"
- "All accessible windows must be fitted with key-operated locks and locked when the property is left unattended"
- "Patio doors must have an additional locking device approved by the insurer"
Pay particular attention to "final exit door" - this is whichever door is the last one locked when leaving the property. On most homes this is the front door, but if you routinely leave through the back door, the back door is the final exit and must meet the same specification.
Common compliance failures
Wooden doors with the wrong lock
A 5-lever lock isn't automatically a BS3621 lock. Generic 5-lever mortice locks sold in DIY shops typically don't carry the kitemark and don't meet the standard. Many properties have these fitted from previous owners or budget-driven refits, and the owner has no idea. A qualified locksmith can usually identify the standard at a glance and replace the lock for £140-£240.
UPVC doors with generic Euro cylinders
Generic Euro cylinders (the kind sold for £8 in a hardware shop) snap in seconds with a basic mole-grip attack. If the policy specifies TS007 3-star and the cylinder fitted is generic, the policy isn't being met. A TS007 3-star anti-snap replacement cylinder is approximately £35-£70 supply-only or £120-£180 fitted.
Patio and French doors with no secondary lock
Many policies specifically require a secondary locking device on patio and French doors - a foot-bolt, a hook-style multipoint, or a key-operated patio lock at top and bottom of the slider. This is one of the most-overlooked compliance gaps in UK homes.
Internal keys left in locks
Most policies require all keys to be removed from internal locks when the property is left unattended - this prevents a burglar from breaking a glass panel and reaching in to turn the key. Insurers can reject a claim purely on this basis if the policyholder left a key in the back door. Habits matter here as much as hardware.
How a locksmith can audit your home
Most independent locksmiths will do a security audit at the same time as a standard job - check every external door against your policy specification, check window locks, and produce a written list of any non-compliant items with replacement costs. There's usually no charge for the audit itself if work is being done at the same visit, and it gives you documented evidence you've checked - useful in any future claim.
For the emergency locksmith service, a security audit is included as part of any post-burglary or break-in repair visit. After a break-in you'll typically be required by your insurer to upgrade locks anyway, so getting the upgrade right matters.
Frequently asked questions
What lock standard does UK home insurance usually require?
For wooden doors with mortice locks, UK insurers most commonly specify BS3621 - the British Standard for thief-resistant lockable mortice deadlocks with at least five levers and a 20mm bolt throw.
For UPVC and composite doors with Euro cylinder multipoint mechanisms, insurers increasingly specify TS007 3-star cylinders or a TS007 1-star cylinder paired with TS007 2-star security door furniture, sometimes with additional Sold Secure Diamond grade requirements for high-value contents.
How do I check if my existing lock meets BS3621?
BS3621 mortice deadlocks carry a small kitemark on the faceplate (visible on the edge of the door when the door is open) showing the BSI kitemark and "BS3621" embossed or laser-etched into the metal.
If the faceplate is unmarked or shows only "BS3621:1980" without the kitemark, it does not meet the current standard. Replacement and refit on a standard wooden door takes a qualified locksmith approximately 60-90 minutes.
What is TS007 3-star and why does it matter?
TS007 is the UK standard for Euro cylinder anti-snap performance, tested by Sold Secure or the Door and Hardware Federation. Cylinders are rated 1-star (basic), 2-star (intermediate, paired with 2-star door furniture for full protection) or 3-star (full anti-snap protection in the cylinder alone).
Lock-snapping is the most common burglary entry method on UPVC doors in the UK; a TS007 3-star cylinder reduces the success rate of this attack from seconds to minutes, by which point most burglars give up.
Will my insurance pay out if my lock did not meet the policy specification?
In practice, insurers can reduce or refuse a claim if the lock specification on the door breached at the time of a burglary did not meet the policy wording. This is one of the most common claim-disputes in UK home insurance.
The amount you save by buying a £20 generic cylinder instead of a £50 TS007 3-star cylinder can easily be lost on a single declined claim. Read the security clause of your policy carefully and ask a qualified locksmith to confirm what is fitted matches what is required.