Home Insurance Lock Requirements | What Voids a Claim

A burglar kicks in the back door of a house on Belper Lane End. Nothing unusual there, sadly. The homeowner calls the police, boards up the door, then calls their insurer. The claim is refused. Not because the burglary didn't happen. Because the mortice lock on that back door was a two-lever, not a five-lever, and the policy schedule said BS3621. A two-lever mortice costs about £15 at a DIY shed. The claim was for £6,400.

This happens. Not constantly, but enough that it's worth spending twenty minutes now understanding what your policy actually demands, and whether your current locks deliver it.

What policies actually say, and where it gets vague

Most home insurance policies describe their lock requirements in one of two ways. Some name a specific standard. Others describe a lock type without naming a standard at all, which is where the arguments happen.

Common phrasings include:

• "Five-lever mortice deadlock conforming to BS3621"
• "Mortice deadlock with a minimum of five levers"
• "Key-operated locks on all accessible windows"
• "Multi-point locking system on final exit doors"
• "Anti-snap cylinder where a cylinder lock is fitted"

That last one is appearing in more and more policies now, particularly with larger insurers. It matters, because a standard euro cylinder with no anti-snap feature will fail a determined attack in under two minutes. If your insurer specifies anti-snap and you've got a basic cylinder, you're potentially uninsured the moment someone walks through that door.

The phrase "final exit door" trips people up regularly. It means the last door you leave through when you go out, locking it behind you with a key from outside. On most Derbyshire terraces and semis, that's the front door. On houses with side gates or rear access, it might be a back door. If your front door has a five-lever mortice and your back door has a rim latch and a two-lever mortice, and the back door is your final exit, you may have a problem.

BS3621: what the standard actually tests

BS3621 is the benchmark British Standard for key-operated security deadlocks. A lock awarded this standard has passed tests covering:

• Bolt strength under direct attack (minimum bolt throw of 20mm)
• At least 1,000 key differs (meaning at least 1,000 mechanically different keys exist in the system)
• Five levers minimum
• Hardened steel bolt to resist cutting
• Anti-saw pins in the bolt
• A deadlocking function, meaning the bolt cannot be pushed back without the correct key

If your policy says BS3621 and your lock doesn't carry that kitemark, the lock is non-compliant. Full stop. The fact that it's a five-lever lock is not enough on its own. A five-lever lock that hasn't been tested to BS3621 may still have inadequate key security or a weak bolt.

The updated standard, BS8621, covers locks that can be opened from inside without a key. These are sometimes required on final exit doors to satisfy fire regulations in rental properties. They comply with BS3621 structurally but allow egress without a key. If your insurer specifies BS3621 and you've fitted a BS8621 lock, check the policy wording. Most insurers accept BS8621 as compliant, but not all. Ask in writing if you're unsure.

Recognised brands that manufacture BS3621-certified locks

Not every lock sold at a builders' merchant carries the kitemark, even if it looks the part. Brands with a strong range of certified five-lever mortice locks include Yale, ERA, and Lockmaster. Mul-T-Lock produce certified mortice locks at the higher end. When we fit a replacement mortice at a job in Milford or Heage, we always check the lock body carries the kitemark stamped on it, not just the packaging claim.

The cylinder clause: where most modern homes fall short

The vast majority of front doors fitted to homes built or re-doored since the mid-1990s use a euro profile cylinder. That cylinder operates the multipoint locking system in a uPVC or composite door. It is, structurally, the weakest point in the door.

Snap attacks work by applying lateral force to the cylinder until the front section breaks off, exposing the internal cam. A burglar with a cheap screwdriver and some leverage can do this. In parts of DE56, including estates around Openwoodgate and the older terraces off the main A6 corridor, we see the results of this regularly.

Insurers have responded in different ways. Some policies now explicitly require an anti-snap cylinder. Others specify a TS007 3-star rated cylinder. Those two things are related but not identical, so it's worth understanding both.

TS007 is the Door and Hardware Federation's specification for cylinder security. It rates cylinders on a star system:

A TS007 3-star rating can be achieved either by fitting a single 3-star cylinder, or by combining a 2-star cylinder with a 2-star escutcheon (the handle or plate around the cylinder). Brands that make 3-star cylinders or certified combinations include Avocet ABS, Ultion, and Mul-T-Lock. ERA and Yale also produce 3-star products in their upper ranges.

If your policy says "TS007 3-star" and you've fitted a generic anti-snap cylinder from a trade counter without verifying its rating, you may not be compliant. Anti-snap is a feature. TS007 3-star is a tested, certificated standard. They're not the same thing.

The like-for-like replacement trap

This is where well-intentioned DIY or a quick cheap fix causes serious problems.

Your five-lever mortice fails. The bolt seizes, the mechanism wears out, or someone loses the key and a locksmith has to drill it. You go to a DIY store, buy a replacement mortice, fit it to the same hole. Job done. Except the replacement is a two-lever lock that doesn't carry the BS3621 kitemark, because those are the ones in the budget section.

Your insurer doesn't know this happened. You don't think to check the policy schedule. Six months later, someone forces the back door. The loss adjuster asks to see the lock, or asks what lock was fitted. The claim fails.

The same trap exists with cylinders. A tenant in a Bridge Hill property changes a cylinder themselves because they want their own key. They buy a 10-pack of cheap euro cylinders from an online marketplace, £8 each. The door now looks locked. It isn't secure in any meaningful sense, and it certainly isn't TS007 rated. If the landlord's policy has a cylinder clause and there's a break-in, the insurer has grounds to reduce or refuse the claim.

As a landlord covering properties around Duffield or Kilburn, you need to know what's in every door, not just what was there when you last visited.

Window locks: the clause almost everyone ignores

Policies almost universally require "key-operated locks on all accessible windows." Accessible means any window a person could reach and climb through, which in practice means ground floor windows, and any first-floor window reachable from a flat roof, garage roof, or extension.

A night latch on a window is not a key-operated lock. A cockspur handle is not a key-operated lock. A window that's been painted shut is not a locked window in the eyes of an insurer.

Most uPVC windows have shootbolt mechanisms operated by the handle. Whether those shootbolts engage correctly depends on the multipoint hardware, typically from brands like GU, Maco, Roto, or Mila. These mechanisms wear. The handle turns, the shootbolts don't travel the full distance, the window looks closed but isn't secured. On older uPVC windows in properties around Ambergate or Crich that haven't had attention in a decade, this is genuinely common.

The check is simple: close the window fully, turn the handle to the locked position, and then try to push the sash. There should be no movement at all. If the sash flexes or lifts even slightly, the shootbolts aren't engaging fully. That's a hardware fault, and it means the window isn't meeting the "locked" requirement.

For timber sash windows, which you'll encounter on older properties in Wirksworth and around the historic streets of central Belper, key-operated sash locks are the standard solution. A sash screw in each top corner is the minimum. Fitch catches alone won't satisfy most policies.

How to actually check your own compliance

Don't start with your locks. Start with your policy schedule and your certificate of insurance. Find the section headed "security" or "security conditions" and read it carefully. Write down exactly what it says for:

1. Final exit door
2. Other external doors
3. Accessible windows
4. Cylinders, if mentioned separately

Then go around each door and window and compare what you find against what the policy requires.

On mortice locks, look for the kitemark stamped on the lock body (not the keyhole cover, the body itself). If you can't see a kitemark and the lock is already fitted, remove the cover plate to check. Count the levers if you're unsure: a five-lever lock will typically have that stated on the lock body or the original packaging.

On euro cylinders, check whether there's any certification printed or stamped on the cylinder itself. Ultion cylinders have their rating on the product. Avocet ABS cylinders carry their certification clearly. An unbranded or generic cylinder has nothing to show an insurer.

On uPVC and composite door multipoint locks, test the mechanism. Lock the door, then push and pull the door from outside while it's locked. If there's any movement, either the multipoint isn't engaging fully or the keep plate alignment is off. Both are fixable, neither is expensive.

On windows, close and lock each one, then test for sash movement. Check that key-operated locks are present on every ground floor window and any first-floor window above a flat roof or accessible surface.

Document what you find. A photo of each lock with its kitemark visible, dated, is useful to have. If you ever need to claim, you're not relying on memory.

Rented properties: who's responsible

Short answer: the landlord is responsible for ensuring the fabric of the property, including the locks, meets the insurer's requirements. If you're a landlord with properties in Ripley or Holbrook covered under a landlord insurance policy, the security conditions apply to you regardless of whether tenants have changed anything.

If a tenant changes a lock without permission and fits something non-compliant, you may have a claim against the tenant for the resulting loss. But you won't necessarily get that money from the insurer. Get your responsibilities clearly into the tenancy agreement: locks may not be changed without written consent, and any replacement must meet or exceed the original specification.

For HMOs or commercial lets, there are additional fire regulation angles around final exit doors that interact with security requirements. A BS8621 lock that allows keyless egress from inside may be legally required. Your insurer needs to know the property type; confirm in writing that the specified lock meets both the insurance condition and the fire requirement.

When a replacement changes everything

One job worth describing here. A homeowner in a detached property near Belper Lane End had composite doors fitted by a local window company about three years ago. Decent doors, PAS24 rated, anti-snap cylinders included at the time of installation. A cylinder failed eighteen months later. The window company sent someone out who replaced the cylinder like-for-like, meaning they matched the size but fitted a generic cylinder from their van stock. No rating, no certification.

When the homeowner renewed their insurance that year, they ticked the box confirming their doors had anti-snap cylinders, because they'd been told they had them. They genuinely believed it.

We got involved because they wanted a quote for a back door lock upgrade. During the visit, the front door cylinder was obviously unrated. We explained the situation. The homeowner contacted their insurer to clarify the position. The insurer confirmed that, had there been a forced entry claim during that period, the cylinder clause would have been a ground for investigation.

Replacing both cylinders with Avocet ABS 3-star products cost £180 fitted. That's not nothing. It's also not £6,400.

Checking before renewal, not after a claim

Insurance renewal is the natural moment to do this audit. You get the new schedule through, you're looking at it anyway, spend another ten minutes going through the property before you sign off the direct debit.

If you find a gap between what the policy requires and what you've got, you have options. You can upgrade the locks to match the policy. You can contact the insurer and ask whether they'd accept an equivalent product with supporting certification. In some cases, particularly with cylinder standards, insurers will note a confirmed compliant product on the policy for a small admin fee, or simply on written confirmation.

What you shouldn't do is assume compliance and find out differently when you need to claim.

Locks Local covers Belper and the surrounding DE postcodes. If you want someone to go through your doors and windows and tell you honestly what you've got and whether it matches a specific policy wording, that's something we'll do. We're usually within thirty minutes across DE56, pricing is given honestly on the call, and we'll tell you if something doesn't need changing as readily as we'll tell you when it does. Call or message if it would help.