Home Insurance Lock Requirements | Check Before You Claim

A burglar gets in through your back door. The police come, you board up the frame, you call your insurer. Then the loss adjuster asks one question: what lock was fitted to that door? You give an answer. They check the policy schedule. Claim refused.

This happens more often than the insurance industry likes to advertise, and more often than locksmiths like to see. The reason is almost always the same: a mismatch between what the policy required and what was actually on the door or window. Not because the homeowner was careless. Because the small print is written in a way that makes it easy to be non-compliant without knowing it.

This post is about finding that mismatch before you ever need to claim.

---

What Insurance Policies Actually Say About Locks

Most household contents and buildings policies contain a security condition. It's usually buried in the general conditions section, not the headline cover summary. The wording varies by insurer, but three requirements appear so consistently they're worth treating as standard:

1. Final exit doors must be fitted with a mortice deadlock or deadlatch to BS3621, or a multipoint locking system to an equivalent standard.
2. Accessible windows must have key-operated locks.
3. Locks must be in working order and actually used when the property is unoccupied.

That third one is almost insultingly obvious. The first two are where the real trouble hides.

What BS3621 Actually Tests

BS3621 is the British Standard for thief-resistant lock assemblies. It's been around since 1963, updated several times, and it covers mortice deadlocks, rim deadlocks, and cylinder deadlocks. The standard tests:

• Resistance to picking and manipulation (500 key combinations minimum for a 5-lever lock)
• Bolt strength (static load and repeated impact)
• Strike plate strength, because the lock is only as good as the box it throws into
• Key security (differs between BS3621 and the updated BS8621, which added key control provisions)

A Yale budget nightlatch does not meet BS3621. Neither does the spring-latch mechanism built into most uPVC door handles. Those are convenience fittings, not security locks in insurance terms.

BS8621 is the successor standard for euro-cylinder-based multipoint systems. It requires the same mechanical resistance but adds provisions for cylinder protection and is the standard you'll see cited for modern composite and uPVC door locks. If your insurer's schedule says "BS3621 or equivalent", BS8621 counts. A lock stamped with neither does not.

---

The Final Exit Door Problem

Here's the scenario that catches people out most often in Lewes and across BN7 and BN8.

You have a Victorian terrace on the Cliffe, a 1970s semi on Landport, or a newer build on Wallands. The front door is solid, well-fitted, has a multipoint lock with a decent cylinder. You've probably been told at some point that it's fine. The back door, though. That's the one nobody thinks about.

The back door is the final exit door on most properties: the last door you lock from the outside before leaving. Policies specifically require this door to have a BS3621 or equivalent mortice deadlock. If it's got only a rim latch, a padlock hasp, or an old single-point euro cylinder on a wooden door with no multipoint system, it's not compliant.

The specific failure modes I see regularly:

• Wooden back doors with a single 2-lever mortice lock (BS3621 requires 5 levers minimum)
• uPVC back doors where the multipoint system has been repaired with a replacement gearbox that isn't certified to BS8621
• Stable doors where the top and bottom are locked separately, neither section having a standard-compliant lock
• Composite back doors fitted with a Sold Secure-rated cylinder but a non-certified multipoint body

The last point matters because cylinder and lock body certifications are separate. A Mul-T-Lock or Avocet ABS cylinder is excellent, but it has to be in a lock body (or multipoint gearbox) that also meets the standard. One without the other gets you halfway there. Halfway doesn't satisfy an insurer.

---

Window Locks: The Clause That's Even Easier to Miss

"All accessible windows must be fitted with key-operated window locks."

Accessible typically means any window a person could reach from ground level, or from a flat roof, garage roof, bay, or extension. In practice, for a two-storey house, that's usually every ground-floor window and several first-floor ones too.

Key-operated is where the arguments start. A lockable tilt-and-turn handle operated by the same key as the door handle probably counts, if the insurer accepts the system as a whole. A cockspur fastener does not. A ventilation stay with a pushpin lock does not. A simple fitch fastener on a sash does not.

For uPVC windows, the most common compliant fittings are:

For timber sash windows, you're looking at Brighton Pattern locks (the old-fashioned screw-pin sash lock) which are generally not accepted, versus locking fitch fasteners with removable keys, which usually are. The detail varies by insurer. If you're on a Southover or Wallands street with original Victorian sashes and no key-operated locks, it's worth checking your schedule before assuming you're covered.

---

Why Like-for-Like Replacement Is a Trap

This is the one that genuinely annoys me, because it's entirely avoidable and happens constantly.

A lock fails. The handle mechanism breaks on a uPVC door on a Nevill estate house, say, or a mortice lock on a cottage in Ringmer strips out. A repair is done. The fitter replaces like-for-like: same style, same fixing pattern, job done. It looks the same. It functions the same. The homeowner is satisfied.

But the replacement gearbox is a cheaper, uncertified version. Or the mortice lock is a new 3-lever unit because that's what the merchant had in stock. Or the cylinder that comes with the new handle pack is an unbranded euro cylinder that meets no standard at all.

The property is now non-compliant, even though the lock was professionally replaced, and nobody told the homeowner.

This is not a hypothetical. The budget end of the hardware supply chain is full of fittings that are functionally adequate but carry no certification. A 3-lever mortice lock will lock a door. It won't satisfy BS3621. An unbranded euro cylinder will turn when you put a key in it. It offers no defined resistance to picking or snapping.

The only way to avoid this is to ask for the standard at the point of replacement. If the fitter can't tell you which standard the new lock meets, that's your answer.

---

How to Check Your Own Property

Work through these points systematically. You don't need any tools for most of them.

Front door

• uPVC or composite with multipoint: Look for a mark on the lock body or the edge of the door where the gearbox sits. Ideally you'll find a BS8621 stamp or a manufacturer's label. If the door was installed by a reputable installer after about 2010 and hasn't had the lock body replaced, it's probably compliant. If you're not sure, pull up the original installation paperwork.
• Timber door with cylinder lock: The cylinder should state its standard on the packaging if you still have it, or you can look up the brand and model. Yale platinum, Avocet ABS, Ultion, Mul-T-Lock MT5+ are examples of cylinders you can verify. The body of the lock (the part morticed into the door) also needs BS3621 certification, separate from the cylinder.
• Timber door with mortice lock only: Open the door and look at the faceplate on the edge. Most quality locks are marked. Five levers is the minimum for BS3621. If it says 2-lever or 3-lever, it's not compliant.

Back door

Repeat the front door checks. Then additionally:

• If there's only a rim latch (a nightlatch, whether Yale or any other brand), that alone is not compliant for a final exit door. It needs supplementing with a compliant mortice deadlock or replacing with a multipoint system.
• If the back door is uPVC and old, check whether the gearbox is still functioning properly. A multipoint that doesn't fully engage because the mechanism is worn offers neither security nor insurance compliance.

Windows

• Walk round the ground floor. Try each window fastener. Does it require a key to open from inside or outside? If yes, it's a key-operated lock. If you can flip it open with no key, it isn't.
• Do the same for any first-floor window reachable from a garage, bay, flat roof, or extension.
• If you've had replacement windows fitted in the last five to ten years, the handles may be locking handles, but verify: some are sold as locking handles and are not actually lockable variants.

Read your schedule

Get out the actual policy document, not the summary. Find the security conditions section. Write down exactly what standard it specifies. Then compare that with what you found above.

If the policy says "5-lever mortice deadlock to BS3621" and you've got a 3-lever lock, you know what needs doing. If it says "multipoint locking system" and your uPVC back door has a single-point latch, same thing.

---

Landlords: Your Exposure Is Larger

If you're renting out a property in Lewes or the surrounding BN7 or BN8 area, the compliance question applies to every property in your portfolio, not just your own home. Your landlord buildings policy will have the same security conditions. Your tenant's contents policy is their own business, but if a break-in leads to a dispute about whether the property was adequately secured, your lock standard becomes relevant there too.

HMO licences in East Sussex can add further requirements beyond what the insurer demands. For licensed HMOs, check with Lewes District Council's private sector housing team for any property-specific conditions.

The practical implication: when you have a lock repaired or replaced at a rental, get written confirmation of what standard the fitting meets. Keep it. If a claim ever arises, that paperwork is worth having.

---

The New-Build Assumption

Owners of properties on newer Lewes developments sometimes assume that because the house is recent, it must be compliant. Often it is. But PAS24 (the standard for doorsets and windows as assembled systems) applies to the door as installed, and builders sometimes specify the minimum that gets them through building regulations sign-off. Minimum isn't always what your insurer requires.

And PAS24 isn't the same as BS8621. A doorset can pass PAS24 testing and still contain a lock body that doesn't independently meet BS8621, because PAS24 tests the whole assembly, not the individual component. If your insurer specifically asks for BS8621, a PAS24 doorset may or may not satisfy that, depending on what the lock body certification says.

If you bought a new-build in the last five to ten years, it's worth asking the developer or doing a certificate check on the specific multipoint system fitted.

---

What to Do If You Find a Gap

First, don't panic. A non-compliant lock is a problem you can fix for a few hundred pounds in most cases. It's much cheaper than a refused claim.

For a timber back door needing a BS3621 mortice deadlock: budget around £120 to £180 fitted for a quality unit from ERA, Union, or Mul-T-Lock, depending on the door condition and whether the rebate needs adjusting.

For a uPVC door where the gearbox needs replacing with a certified unit: allow £90 to £150 fitted for a standard gearbox replacement. More if the door is a non-standard size or the frame is damaged.

For window locks: a ground floor with six to eight sash windows or casements needing key-operated locks is typically £150 to £300 in hardware and fitting. uPVC casements are often cheaper per window because the locking handles just swap in.

Get any upgrade documented. Ask for the standards in writing. Keep the invoice with your policy.

---

If you want someone to check your property before an insurer does, Fort Secure covers Lewes and the BN postcodes and can usually get to you within 30 minutes. We'll go door by door and window by window, tell you what meets the standard and what doesn't, and quote you honestly for anything that needs work. No call-out fee on the assessment if we do the work. Give us a ring, or drop a message through the site.