Home Insurance Lock Requirements | Check Before You Claim, Not After

A claim gets rejected. Not because the burglar was especially clever, not because the insurer is acting in bad faith, but because the lock on the back door was a five-lever mortice that someone swapped out for a three-lever when the original seized up. Like-for-like in appearance. Not like-for-like in the policy schedule.

This happens. It happens in Richmond, it happens on the Petersham Road and on streets in Ham and in the new-build flats around St Margarets. And the worst part is that the homeowner almost always had no idea there was a requirement to meet in the first place.

So. Let's be specific about what insurers actually ask for, what the standards mean, and how you check your own property today.

What Your Policy Schedule Actually Says

Most home insurance policies contain a security condition. It sits in the definitions or conditions section, not the headline cover summary. It usually looks something like this:

All external doors must be fitted with a mortice deadlock conforming to BS3621, or a key-operated multipoint locking system.

Sometimes it adds:

Ground floor and accessible windows must be fitted with key-operated window locks.

Sometimes it references specific stars or accreditations. Sometimes it says nothing useful at all and refers you to a schedule that wasn't included in the email.

The two clauses that catch people out most reliably are the final exit door clause and the accessible window clause. Both are worth understanding in their own right.

The Final Exit Door Clause

Every home has at least one door that can't be double-locked from the outside because someone is still inside. Your front door, if it's a uPVC with a multipoint lock, can be deadlocked when you leave. The back door, which you might exit through to check the bins and then close behind you on a nightlatch, often can't.

Insurers know this. Many policies explicitly carve out a "final exit door" exception, meaning that door doesn't have to be deadlocked provided a nightlatch conforming to BS8621 is fitted. BS8621 is the standard for nightlatches specifically designed for final exit doors. The distinguishing feature: it can't be held back (no hold-back function), so it always snaps shut and latches. It also has a deadlocking feature so the latch can't be pushed back from outside.

If your final exit door has a standard Yale-type nightlatch, that's BS3570 territory, not BS8621. It may not satisfy the policy condition. Check the standard printed on the faceplate of the lock body, or the packaging if it's recent.

Brands that make BS8621-compliant nightlatches include Yale (the 89 series), ERA, and Lockmaster. They're not expensive, typically £30 to £60 for the lock alone. The fitting is a one-for-one swap in most cases.

The BS3621 Mortice Lock Requirement

BS3621 is the British Standard for key-operated locks. It specifies, among other things:

• A minimum of five levers (or a cylinder with equivalent picking/drilling resistance)
• A bolt throw of at least 20mm
• A steel bolt
• Anti-saw protection in the bolt (hardened steel rollers or inserts)
• Resistance to a defined set of manipulation attacks

A three-lever mortice lock does not meet BS3621. Neither does a two-lever. And both are still sold in high-street hardware shops, in the same size cases as five-lever locks, in the same finishes. They look identical to a non-specialist. They fit the same cutout in a timber door.

If someone has replaced a five-lever BS3621 mortice on your property with a cheaper three-lever, your policy condition may now be unmet. The compliance risk transfers to you the moment you buy the property, or the moment the replacement happens.

How to check: The number of levers is usually marked on the forend (the metal plate visible on the door edge) or on the keyhole cover. A five-lever key has a noticeably more complex blade than a two or three-lever key. If you're not sure, a locksmith can confirm in under a minute. The BS3621 kite mark should also be visible on the lock body when the door is open.

Multipoint Locks and the PAS24 Question

Most uPVC and composite doors fitted since the mid-2000s use a multipoint locking system. One handle lift engages multiple bolts and hooks along the door edge. These are not covered by BS3621, which is written for traditional mortice locks.

Insurers have caught up with this. Many policies now say the door must meet PAS24, which is the standard for enhanced security performance for doorsets. PAS24 tests the complete door and frame assembly, not just the lock in isolation. A PAS24 doorset resists a defined set of physical attacks: manual attack, key manipulation, and destructive bypass.

The complication: you can't retrofit PAS24 compliance. It's a doorset certification, awarded to the door, frame, glazing, and hardware together when tested as a unit. If your uPVC door was supplied and fitted as a PAS24 doorset, that's fine. If someone has since replaced the cylinder, the multipoint mechanism, or the handle with non-compliant parts, the original certification is no longer meaningful.

For multipoint mechanisms specifically, look at brands like GU, Fuhr, Maco, Roto, Mila, and Winkhaus. All make mechanisms that appear in PAS24-certified doorsets. The mechanism alone doesn't confer PAS24 status, but fitting a recognised security-grade mechanism alongside a TS007 3-star cylinder is the practical approach most insurers accept.

Cylinders: The TS007 Star Rating

If your policy mentions cylinders at all (many don't, explicitly), it may reference TS007, which is the technical specification for euro profile cylinders. It runs from one to three stars.

A TS007 3-star cylinder, such as the Avocet ABS, Ultion, or Mul-T-Lock MT5+, resists snap attacks specifically. Snap is still the most common method used to bypass euro cylinders in the UK. The cylinder snaps at a weak point under leverage, exposing the internal cam, and the door opens in seconds.

Standard cylinders, including many branded ones sold as "high security" in DIY chains, are not TS007 3-star. The rating has to be earned through independent testing. If your policy references TS007 3-star and your cylinder isn't rated, you're technically non-compliant.

Replacement cost: a TS007 3-star cylinder runs £25 to £60 supplied. Fitting takes fifteen minutes. It's the single cheapest meaningful security upgrade on a uPVC door.

The Accessible Window Clause

Accessible windows means any window a burglar can reach without a ladder: ground floor windows, basement windows, and any window reachable from a flat roof, bay roof, or outbuilding. Insurers routinely require these to be fitted with key-operated window locks.

This matters because sash windows on older properties in Richmond Hill, Kew, and parts of East Sheen often have no locking hardware at all, or have the original sash fastener, which resists nothing. A standard sash stop or Brighton fastener is not a key-operated lock. Dual screws or surface-mounted sash locks that take a key are.

For casement windows, a key-operated espagnolette or a cockspur handle lock that requires a key is the standard fix. Winkhaus and Mila make good casement window hardware. For sash windows, dual screws (sometimes called sash window locks) take a common key and are fitted into the meeting rail.

If you've got aluminium sliding doors opening onto a garden, a Richmond landlord favourite, check whether the anti-lift blocks are in place and whether the handle lock is key-operated. Many aren't.

Like-for-Like Replacement: The Specific Trap

This is where claims fall apart. A lock fails. A handyman, a builder, or a well-meaning previous tenant replaces it with "the same type of lock." The physical dimensions match. The door works. Nobody checks the standard.

Three scenarios this happens in:

Scenario one. A five-lever BS3621 mortice on a timber back door seizes after years of use. A builder replaces it with a three-lever from a trade counter because it's in stock and fits the cutout. Job done. Claim rejected eighteen months later.

Scenario two. A euro cylinder on a uPVC front door in a North Sheen terrace gets replaced after a lockout. The locksmith (not us, for the record) fits a standard cylinder rather than a TS007 3-star. The policy required 3-star. The cylinder looks identical. The replacement cost is £10 less. The compliance gap is significant.

Scenario three. A landlord in Twickenham has a flat with composite doors. The original multipoint mechanism fails. A general maintenance contractor fits a like-for-like mechanism by dimensions but from a manufacturer not on the insurer's approved list. The doorset's original PAS24 status is now questionable.

In each case, the mistake is invisible until a claim. At which point it's too late.

How to Check Your Own Property

Do this walk-round now. It takes twenty minutes.

Front door (timber) - Open the door and look at the forend of the mortice lock. Count the levers if stated, look for the BS3621 kite mark. - Check the nightlatch if there is one. Does the faceplate state BS8621? If not, is this your final exit door? If yes, you may have a gap. - Look at the cylinder if it's a rim lock setup. Is there a TS007 star rating stamped or labelled?

Front door (uPVC or composite) - Lift the handle and turn the key. All bolts should engage. If the handle lifts without resistance or the hooks don't deploy, the mechanism needs attention. - Look at the cylinder. Is it TS007 3-star? Avocet ABS, Ultion, Mul-T-Lock MT5+, and ERA Fortress are the names to recognise. A plain brass cylinder with no branding is almost certainly not. - Check whether the door was supplied as a PAS24 doorset. If you have original paperwork from the installer, it will say so.

Back door and side gate access - Same cylinder and mortice checks as above. - If this is your final exit door (the last one you use before leaving), is the nightlatch BS8621? - Is there a mortice deadlock as well? Many policies require both a nightlatch and a deadlock on timber back doors.

Ground floor and accessible windows - Open each window. Is there a key-operated lock, not just a standard handle or turn-button fastener? - Sash windows: are dual screws fitted into the meeting rail? Test that they actually engage. - Aluminium sliding doors: is the handle key-lockable? Are the anti-lift blocks present in the top track?

Garage and outbuildings - Internal access from a garage to the main house is often treated as an external door by insurers. Check your policy wording. A five-lever BS3621 may be required there too. - Up-and-over garage doors are a separate topic, but if there's a pedestrian door in the garage, apply the same checks.

What Your Policy Document Actually Looks Like

Pull it up now. Search the PDF for these terms: "locks," "BS3621," "British Standard," "key-operated," "security conditions." The relevant clause is usually in a section headed "Conditions" or "Policy Conditions" or "Security Requirements." It is not in the summary of cover.

If you find a clause you don't understand, ring your insurer and ask them to clarify it in writing. Keep the email. If you later change a lock, keep the receipt and the product packaging showing the standard it meets.

If you've recently bought a property and don't have the original door documentation, it's worth having a locksmith assess the existing hardware. In Richmond, we see a lot of properties where the locks fitted during a 1990s or early 2000s refurbishment are technically compliant but badly worn, and a worn five-lever is not the same as a working five-lever.

Landlords: Your Exposure Is Doubled

If you rent a property in Richmond, Ham, Mortlake, Teddington, or anywhere else in the borough, you have building insurance on the property and your tenants may have contents insurance. Their contents insurer will ask the same questions about lock compliance if they claim after a break-in. If the locks didn't meet BS3621 or the relevant standard, their claim may fail, and they may come back to you.

Landlords also need to be aware that any lock replacement done by a maintenance contractor between tenancies is their responsibility to check. A contractor fitting a non-compliant lock is not your insurer's problem.

A simple protocol: whenever a lock is replaced on a rental property, note the brand, model, and standard on your maintenance log. It takes thirty seconds and could matter enormously later.

Prices for Getting Compliant

To give you a realistic sense of what fixing any gaps costs:

These are realistic 2024 figures for the Richmond area. They're not quotes. Call for a quote.

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Rapid Response Locksmiths covers Richmond and the TW postcodes, TW9 and TW10 in particular but also out to Twickenham, Teddington, Hampton, Isleworth, Whitton, and Barnes. Average arrival is under thirty minutes on most calls. Pricing is given honestly on the phone before anyone comes out. If you want a lock check before you ever need to make a claim, that's a straightforward job we're happy to do.