Eltham Locksmith Service Team
Local locksmith team
14 Oct 2026 10 min read
If your home insurer has ever asked whether your front door has a BS3621 lock, you are not alone. It is one of the most common questions homeowners in Eltham and across London receive when they take out or renew a buildings or contents policy — and one of the least explained. Getting the answer wrong can mean a claim is reduced or even refused, so it is worth understanding exactly what the standard means, why insurers care about it, and what you can do about it today.
This guide cuts through the jargon. Whether your front door is a traditional timber door with a Yale nightlatch, a modern uPVC door with a multipoint lock, or anything in between, you will find clear and practical advice below. Where a job calls for a trained locksmith London residents can trust, our team at Eltham Locksmith is available around the clock.
What BS3621 Actually Means — and Why It Exists
BS3621 is a British Standard published by the British Standards Institution that sets minimum security requirements for key-operated thief-resistant locks. When a lock carries the BS3621 kitemark, it has been independently tested and confirmed to resist a defined set of attack methods — including picking, drilling, and manipulation under sustained force. The standard covers mortice deadlocks (the type you turn a key in from outside and which throws a solid bolt into the frame), rim deadlocks, and certain mortice sashlock designs. A five-lever mortice deadlock to BS3621 is the benchmark most insurers have in mind when they write that requirement into your policy wording.
The standard has been around in various forms since the 1960s, which is why it has become the industry shorthand for 'a lock that actually resists a burglar rather than merely inconveniencing them.' An older two-lever lock, or a basic nightlatch (sometimes called a Yale lock) on its own, will not meet the standard. Those locks have their place, but they are designed for convenience, not resistance. BS3621 locks are engineered to slow an intruder down long enough that they give up or attract attention — which, statistically, is exactly what most opportunist burglars do when met with genuine resistance.
Why Your Insurer Asks for It — the Insurance Policy Side
Home insurers price risk. A front door secured only by a nightlatch can be forced in seconds with a credit card or a sharp kick. A BS3621 five-lever mortice deadlock fitted correctly into a solid timber frame is a qualitatively different proposition. Insurers therefore include a lock clause — sometimes called a security warranty — in their policy terms. If your locks do not meet the stated standard at the time of a break-in, the insurer may argue that you have not taken reasonable precautions, and they may reduce or decline your claim.
It is worth reading your policy schedule carefully. Some policies say the BS3621 lock is required only on the front and back doors. Others extend the requirement to all external doors including those leading from an integral garage or a garden outbuilding. A small number of policies distinguish between timber doors (where a mortice deadlock is typically specified) and uPVC or composite doors (where a multipoint locking system meeting PAS 24 may be accepted as an equivalent). If you are unsure, call your insurer and ask them to confirm in writing exactly which doors and which standards apply — that written confirmation can matter if you ever need to make a claim.
How to Check the Locks on Your Own Front Door Right Now
Start by looking at your front door from the inside. If you have a timber door, you are likely to see two separate locking points: a nightlatch (the spring-loaded latch that catches automatically when the door closes) and a deadlock (a keyhole lower down, usually around a third of the way up from the bottom of the door). The deadlock is the one that matters for BS3621. Turn your key and watch what happens — a correctly functioning mortice deadlock will throw a solid rectangular bolt across into the frame with a firm, positive action. If you can push the bolt back with your finger once it is extended, that is a rim lock, not a mortice deadlock, and it almost certainly does not meet BS3621.
On the inside face of a BS3621 mortice deadlock, there should be a small keyhole cover plate. Remove it (usually just a push or a small screw) and look for the BS3621 kitemark — a capital K containing a circle — and the number 3621 stamped or engraved into the lock case. No marking means no guarantee of compliance. For uPVC and composite doors, look at the multipoint lock mechanism on the edge of the door (the long metal strip with multiple hooks or bolts). There should be a mark on the cylinder or the lock body confirming it meets PAS 24 or TS007 standards. If your door has a euro cylinder and there is no anti-snap marking on it, that is worth addressing separately — euro cylinders without anti-snap protection are vulnerable to a quick-and-silent attack method called cylinder snapping that has become common in South East London, including areas around Eltham, Well Hall Road and the streets leading off Footscray Road.
Lock Change London — When to Upgrade and What to Expect
If your check reveals that your locks do not meet your insurer's requirements, the solution is a lock change or a door lock replacement. This is straightforward work for a skilled locksmith, and in most cases it can be completed in under an hour without any damage to your door. For a timber door, the existing mortice deadlock case is removed and a BS3621-compliant five-lever lock is fitted in its place. If the door frame is in good condition and the existing cut-out is the right size, the job is clean and quick. If the frame is damaged — perhaps from a previous forced entry — the locksmith will need to pack and reinforce it before fitting the new lock, which takes longer.
For uPVC and composite doors, a lock change London homes with multipoint systems commonly need involves replacing the euro cylinder rather than the entire mechanism. Upgrading to a TS007 three-star anti-snap cylinder not only addresses the snapping vulnerability but will also often satisfy an insurer's security requirement, particularly when combined with a handle that keeps the multipoint bolts engaged. When you call us, we will ask about your door type, the existing lock make if you know it, and your postcode district so we can confirm an exact price before anyone travels to you. The final quote reflects the lock specification needed, the time of day, and what parts are required — there are no surprises on the doorstep. If you would rather not wait to find out where you stand, call 020 3757 5833 and one of our team will talk you through your options straight away.
Keeping Your Cover Valid — Practical Steps for Eltham Homeowners
Once you have confirmed or upgraded your locks, there are a few habits worth building. Keep the receipt and any product documentation for your new BS3621 lock — these are useful evidence if you ever make a claim. If you are a tenant, you should check your tenancy agreement before changing any locks; in most cases you will need written permission from your landlord or letting agent, though a landlord cannot unreasonably refuse a reasonable security upgrade. If you live in a flat, remember that your insurer's requirement applies to your own front door; the security of the communal entrance is a separate matter that falls to the freeholder or the managing agent.
Renewing your policy is also a good prompt to re-read the security wording, because insurers do occasionally update their requirements between renewal cycles. A lock that was compliant under last year's terms may need to be supplemented under this year's. Finally, if you are ever locked out London can feel like a long way from help at two in the morning — but our team covers Eltham and the wider South East London area around the clock. We send a locksmith straight away and are usually with you in about 30 minutes. We will get you back inside safely, and if your lock needs attention afterwards we can deal with that in the same visit. For anything urgent — or simply to get advice — call 020 3757 5833, any time, day or night.
Frequently asked questions
My uPVC door has a multipoint lock — does that count as BS3621 for insurance purposes?+
Not automatically, no. A standard multipoint lock on a uPVC or composite door meets a different set of requirements to BS3621, which was originally written around mortice deadlocks for timber doors. Many modern home insurance policies do accept a multipoint locking system that meets PAS 24 as an equivalent security level, but the exact wording varies between insurers. The safest approach is to contact your insurer and ask them to confirm in writing whether your existing door and lock arrangement satisfies their security warranty. If your euro cylinder does not carry a TS007 anti-snap rating, that is worth upgrading regardless — anti-snap cylinders address a genuine and common vulnerability on uPVC doors across South East London.
I have just moved into a house in Eltham — should I change the locks before I notify my insurer?+
Changing the locks when you move into a new property is good practice regardless of insurance, because you have no way of knowing how many copies of the previous keys exist. From an insurance perspective, what matters is that the locks in place meet your policy requirements from the moment your cover begins. If you change the locks to BS3621-compliant ones promptly after moving in, you are in a stronger position than if you leave the original locks in place and only act after something goes wrong. Call us and we can carry out a door lock replacement London move-ins commonly need as part of the same visit — we cover Eltham and the surrounding area and can usually be with you the same day.
How do I know if the locksmith I call will fit a genuinely BS3621-compliant lock rather than just telling me it is?+
Ask the locksmith to show you the kitemark on the lock packaging before the work begins, and again on the lock case once it is fitted. A BS3621 lock will carry the BSI kitemark — a stylised K inside a circle — along with the number 3621, either printed on the box or stamped into the metal. Any trained and experienced locksmith should be able to point this out without hesitation. At Eltham Locksmith we carry BS3621-rated stock and are happy to show you the product details before we start. We are also fully insured, so if anything is not right you have genuine recourse — not just a verbal assurance.
What happens if I am locked out of my house late at night — will calling an emergency locksmith London affect my insurance?+
Calling an emergency locksmith London for a genuine lockout will not, in itself, affect your insurance. The concern insurers have is about the security of the lock after the lockout is resolved. If the locksmith has to drill or damage a lock to gain entry, the door must be re-secured to at least the same standard before you leave it unattended. A skilled locksmith will almost always be able to open a door without destructive methods; if any damage does occur, the lock should be replaced before you go to bed. We handle both the entry and any necessary lock change or upvc door lock repair London properties may need as part of the same call-out, so your door is left secure and your policy remains valid.
