British Standard locks
British Standard locks (BS3621): do you need one, and for which door?
Stafford, Wolverhampton and Cannock. Insurance-grade locks fitted, honestly explained.
If your home insurance renewal has just asked for "British Standard BS3621 locks" and you're not sure whether you need one, this is the page. Here's the part that catches most people out: BS3621 is a timber-door standard. It's a 5-lever mortice deadlock with the BSI Kitemark, and it's the right answer on a wooden front or back door. But if your door is uPVC or composite, BS3621 can't be fitted to it at all, and what your insurer actually wants there is a TS007 3-star cylinder instead. Work out which door you've got first (the decision block below does it in one step), and you'll know exactly what you need before anyone quotes you. From £120 fitted for a timber-door mortice, no call-out fee.
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What a British Standard (BS3621) lock actually is
"British Standard lock" almost always means a lock that meets BS3621. It's the standard the British Standards Institution sets for thief-resistant mortice and rim locks, the kind fitted to timber doors. A lock that meets it has been independently tested to resist drilling, picking and forcing, and it carries the BSI Kitemark stamped into the faceplate along with the words "BS3621". Most UK home insurers name BS3621 as the minimum lock they expect on a wooden final-exit door, and a fair number won't pay a theft claim if the lock that was beaten didn't meet it.
The single most important thing to understand, and the thing that saves people the most money, is that BS3621 is a timber-door standard. It applies to 5-lever mortice deadlocks and rim nightlatches on wooden doors. It does not apply to uPVC or composite doors, because those use a multi-point mechanism and a euro cylinder, which are different hardware entirely. The Master Locksmiths Association explains the BS3621 British Standard in detail. The decision block below works out, in one step, which standard your door actually needs.
Timber or uPVC? The question that decides everything
You can answer the whole "do I need a British Standard lock" question by answering one simpler one: what is the door made of? Work down these three and you'll know exactly what your insurer is really asking for, and what (if anything) needs to change.
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You have a TIMBER door (wood, painted or stained): BS3621 is your standard
A solid or panelled wooden front or back door takes a mortice lock cut into the edge of the door, or a rim nightlatch fixed to the face. The insurance-grade version is a BS3621 5-lever mortice deadlock carrying the BSI Kitemark. This is the genuine "British Standard lock" your policy is asking for, and it is what I fit on timber final-exit doors. From £120 fitted for a like-for-like swap.
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You have a uPVC or composite door: BS3621 does NOT apply, you need TS007 instead
A uPVC or composite door uses a multi-point mechanism with a euro-profile cylinder, which is completely different hardware. A BS3621 mortice lock physically cannot be fitted to it. When an insurer writes "BS3621" and you have a uPVC door, what the policy actually accepts is a TS007 3-star Kitemark cylinder (or a 1-star cylinder behind 2-star handle hardware), with PAS3621 covering the mechanism. So you do not need BS3621 and you cannot have it on this door. The full honest guide to that upgrade is on my anti-snap locks page.
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Not sure which you have, or your policy names both? Send a photo first
Plenty of houses have a timber back door and a uPVC front, or the other way round, and the insurer wants the right standard on each. Some policies even list "BS3621 mortice OR TS007 3-star cylinder" as alternatives. Before you spend anything, WhatsApp me a photo of each external door and the lock on it. I will tell you exactly which standard each door needs and what, if anything, has to change. Free, no obligation.
BS3621 vs TS007 vs PAS3621 vs SS312: the standards map
Four names get thrown around on insurance forms and they aren't interchangeable. Here's what each one actually covers and which door it belongs to, so you can match the wording on your schedule to the right bit of hardware.
- BS3621. The British Standard for 5-lever mortice deadlocks and rim locks on timber doors. Independently tested, BSI Kitemarked. This is the "British Standard lock" insurers name for wooden final-exit doors.
- TS007. The BSI Kitemark scheme for euro cylinders (and the security handles around them) on uPVC and composite doors. Rated in stars: a 3-star cylinder is snap-resistant and compliant on its own; a 1-star cylinder needs 2-star handle hardware to match it.
- PAS3621. The multi-point-lock equivalent of BS3621 for uPVC and composite doors, covering the keyed mechanism (the strip with the hooks). It sits alongside the TS007 cylinder rating on the same door.
- SS312 (Sold Secure Diamond). A cylinder grade from Sold Secure, a separate test body to BSI but compatible with TS007. Diamond is their top cylinder grade. Many premium 3-star cylinders carry both the TS007 and SS312 stamps. If your policy names "Sold Secure Diamond", look for that logo as well as the Kitemark.
In plain terms: timber door means you're in BS3621 territory; uPVC or composite door means you're in TS007 / PAS3621 territory. SS312 is an alternative cylinder badge that lives in the same uPVC world as TS007. The mistake that costs money is trying to make a uPVC door "BS3621 compliant", which isn't a thing.
What your home insurer actually requires
UK home insurance isn't standardised on locks, so the wording varies and it's worth reading your own schedule rather than guessing. The common patterns I see are: "BS3621 5-lever mortice deadlock to all timber final-exit doors"; "BS3621 mortice OR TS007 3-star cylinder" (giving you the right option for whichever door you have); and "key-operated locks to all accessible windows" tucked further down (more on that below). Some policies make no specific demand until a claim is made, at which point they check what was fitted. If you're not certain, ask your insurer or broker in writing before you spend anything.
What an honest locksmith will tell you about the "BS3621" clause
If your insurer has written "BS3621" and you have a timber door, you need a Kitemarked 5-lever mortice deadlock, and a like-for-like swap is from £120 fitted, not the £300-plus some national numbers quote. If your insurer wrote "BS3621" and you have a uPVC door, do not pay anyone to "change the lock to British Standard", because BS3621 can't be fitted to that door. What the policy accepts there is a TS007 3-star cylinder, from £130 fitted. Either way you do not need a whole new mechanism, and you should never be charged for fitting a standard that physically can't go on your door.
How to tell if your lock is already BS3621
You don't need a locksmith to check a timber door. Open the door and look at the faceplate, the metal strip on the edge of the door where the bolt comes out. You're looking for two things stamped into it:
- The BSI Kitemark. A small heart-shaped logo with a stylised K inside it, engraved or stamped into the faceplate. This is the mark that says the lock was independently tested and certified.
- The standard number "BS3621". Usually right next to the Kitemark, often with a year (for example "BS3621:2017"). Kitemark plus BS3621 stamp means you're compliant on that door.
- No markings, or just a brand name. If there's no Kitemark and no BS3621 stamp, the lock almost certainly isn't British Standard, even if it feels heavy or has several levers. A 5-lever BS3621 deadlock also tends to take a chunkier key than an old 2 or 3-lever lock.
If you'd rather not squint at it, take a photo of the faceplate and the key and WhatsApp it to me on 07386 341725 with your postcode. I'll tell you on the spot whether you're already compliant, what an upgrade would cost if you're not, and whether you actually need one. Free to ask, no upsell if the honest answer is "you're fine".
The window-lock clause people forget
It's not just doors. A lot of UK home insurance policies quietly require key-operated locks on all easily accessible windows, and it's the clause people overlook until a claim is questioned. "Accessible" usually means every ground-floor window, plus any upstairs window that can be reached from a flat roof, porch, garage or extension. The exact wording is on your schedule, so it's worth a read.
If your windows already have the little key-locking handles or espagnolette locks and the keys turn, you're most likely fine. If they're seized, the keys are long gone, or they were never fitted, that's a gap worth closing before it matters. I can check the windows at the same time as the door, free the seized ones, and fit key-locking handles where they're missing, quoted on the day once I've seen them. Doing it in one visit means there's no second call-out to pay for.
Recent British Standard jobs in Stafford, Wolverhampton and Cannock
Three recent cases: a genuine timber-door BS3621 upgrade, a uPVC owner I stopped from paying for an impossible "British Standard" job, and a back-door-plus-windows insurance fit. Real prices on the receipt, sat next to what a national number quoted for the same work. Customer details lightly anonymised at their request.
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Thursday 21 May 2026 at 11.00am · Stafford
Mr Hartley, Stafford
Renewal letter on a timber-fronted terrace in ST16 named "BS3621 5-lever mortice deadlock to the front door". The door had only an old 3-lever lock and a surface nightlatch, neither Kitemarked. He sent me a photo of the faceplate on WhatsApp so I could confirm the size before I set off.
A national number quoted the customer £180Paid to me £130Fitted a BSI Kitemarked BS3621 5-lever mortice deadlock (Union 2C-pattern) as a like-for-like into the existing mortice. Photographed the Kitemark and BS3621 stamp on the faceplate and emailed it for the insurer. 30 minutes on the doorstep, no call-out fee. A national number had quoted £180 for the same job.
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Monday 18 May 2026 at 2.15pm · Wolverhampton
Mrs Okafor, Wolverhampton
Rang convinced she needed "BS3621 locks" because the insurer form said so, and a national locksmith had quoted £320 to "change the lock to British Standard". Her front door is uPVC with a euro cylinder. BS3621 cannot be fitted to it, so the quote was for something that does not exist on that door.
A national number quoted the customer £320Paid to me £140Explained the timber-vs-uPVC difference on the phone, then fitted what the policy actually accepts on a uPVC door: a TS007 3-star Kitemark anti-snap cylinder, from £130. Photographed the 3-star stamp for the insurer, who accepted it with no premium loading. Saved her £180 and stopped her paying for a job that was impossible on her door.
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Wednesday 27 May 2026 at 10.00am · Cannock
Mr Doyle, Cannock
Older semi in WS11 with a timber back door. The insurer required BS3621 on the final-exit door AND key-operated locks on accessible windows. The back door had a non-BS lock, and two ground-floor window locks were seized with the keys long lost.
A national number quoted the customer n/aPaid to me £190BS3621 5-lever mortice deadlock fitted to the timber back door, plus two seized key-locking window espagnolettes freed and re-keyed while I was there. Photographed every Kitemark stamp for the claim file. Did the lot in one visit so there was no second call-out, and showed him which upstairs windows the policy did and did not count as accessible.
The British Standard for timber-door locks is documented by the Master Locksmiths Association's BS3621 guidance. My from-price for a like-for-like BS3621 5-lever mortice deadlock is £120 fitted; a uPVC door needs a TS007 3-star cylinder instead, from £130 fitted.
What customers say
Verified Google reviews from homeowners across Stafford, Wolverhampton, Cannock and the surrounding villages.
Amazing service - Couldn’t be happier - Very efficient and a super lovely guy too - Highly recommended to anyone
After I lost my keys, I was extremely stressed out as I looked everywhere. It was pouring down and I had no shelter. I called these Locksiths and they came out to me straight away. No longer had they arrived they managed to unlock my door and change the locks for me. I even replaced the window locks too as they got lost in the move. Thank you so much! I would recommend these guys as they were very sympathetic and helpful in all ways.
Great service on time and very reliable would definitely recommend to others came out for a simple job in Cannock when others wouldn’t
Great service from Lockerfella Locksmiths! I’m based in Wolverhampton and was impressed by the fast response, professional work, and fair prices. Reliable and highly recommended! ⭐⭐⭐⭐⭐
The best service in a long time ! Sean came out to me from lockerfella locksmiths in Wolverhampton and fixed around 3/4 locks for me was incredibly efficient and very polite and friendly , will defiantly know who to call for next time thank you so much!
Sean from lockerfellla locksmith came to our rescue as we had left our keys inside our house in Cannock. Had us back in within minutes. Great service.
Awesome company ! Came out to replace 4 locks in Wolverhampton and were amazing all done well. I highly recommend Lockerfella Locksmiths
Called Lockerfella Locksmiths yesterday in Stafford to have new handles and locks on our backdoor. Very reasonably priced. Got back to us within seconds. Top man, and extremely polite. Would highly recommend.
Prices
From-prices for British Standard and insurance work
The figures below are floor prices for the most common insurance-driven jobs. They include attendance and labour with no separate call-out fee. The full price list with covers and affects sits on the dedicated pricing page.
- BS3621 5-lever mortice deadlock (timber door), like-for-like supply & fit from £120
- TS007 3-star anti-snap cylinder (uPVC / composite door), fitted from £130
- Standard uPVC euro cylinder change, fitted from £90
- Key-operated window locks freed or fitted quoted on the day
- Fresh mortice cut into an un-prepared timber door quoted on the day
No VAT added on top. No call-out fee. I photograph the Kitemark stamp once the lock is in, so you can email the evidence straight to your insurer. See the full price list and what each one covers →
About the locksmith
The locksmith answering your call
I'm Sean Hamilton. I run Lockerfella as a one-man-band out of Brewood. If your insurance renewal has asked for British Standard or BS3621 locks, send me a photo of the door and the lock on WhatsApp with your postcode. I'll tell you whether it's a timber door that needs a BS3621 mortice, a uPVC door that needs a TS007 cylinder, or whether you're already compliant. The price on the phone is the price on the receipt. No call-out fee. No selling you a standard that won't fit your door.
- 30+ years fascinated by locks. I've been picking, stripping and studying locks for the love of it for over 30 years. Lockerfella is what happens when a lifelong interest in how locks work becomes the day job.
- Trained and certified. Certificate of Locksmith Skills from A'Jam Locksmiths covering cylinder, mortice, padlock, wafer and euro lock picking, plus re-keying and mortice bypassing.
- Basic DBS checked, £1M insured, 12 months workmanship guarantee. Redacted DBS and insurance certificates are published on the About page, with originals available to view in person before work starts.
- One man, one van, one phone number. The phone rings on me directly. No call centre. No third-party fitter. If I quote you a price, that's the price you pay.
Common questions about British Standard locks
Straight answers on BS3621, timber vs uPVC doors, Kitemark stamps, home insurance, 3-lever vs 5-lever, and what an honest British Standard lock fit actually costs.
Do I need a British Standard lock for my home insurance?
Usually, yes, on a wooden front or back door. Most UK home insurers name British Standard BS3621 in the policy wording as the minimum lock on timber final-exit doors, and a lot of them will not pay a theft claim if the lock that was forced did not meet it. BS3621 means a 5-lever mortice deadlock that has been independently tested and carries the BSI Kitemark. The thing to know is that BS3621 is a timber-door standard. If your door is uPVC or composite, BS3621 does not apply to it and your insurer is really asking for the uPVC equivalent instead (see the next question). Check your own policy schedule, or send me a photo of the lock and the door on WhatsApp and I will tell you where you stand before you spend anything.
Can you fit a BS3621 lock to a uPVC door?
No, and this is the single most common mix-up I get called about. BS3621 is the standard for mortice and rim locks fitted to timber doors. A uPVC or composite door uses a multi-point locking mechanism with a euro-profile cylinder, which is a completely different bit of kit, so a BS3621 mortice lock physically cannot be fitted to it. When an insurer writes "BS3621" on a renewal form and the customer has a uPVC door, what the policy actually accepts on that door is the uPVC equivalent: a TS007 3-star Kitemark cylinder (or a 1-star cylinder behind 2-star handle hardware), and PAS3621 for the multi-point mechanism itself. So if your door is uPVC, you do not need BS3621 and you cannot have it. You need the right uPVC upgrade, which is covered in full on my anti-snap locks page. Ring me with the door type and I will point you at the correct one rather than sell you something that will not fit.
How do I know if my lock is already BS3621?
Open the door and look at the faceplate, which is the metal strip on the edge of the door where the bolt comes out. A BS3621 lock has the BSI Kitemark stamped into that faceplate (the Kitemark looks like a heart shape with a stylised K inside it) followed by "BS3621", often with the year, for example "BS3621:2017". No Kitemark and no BS3621 stamp means it almost certainly is not British Standard, even if it feels solid and has several levers. A quick second check on a mortice lock: a 5-lever BS3621 deadlock usually needs a chunkier key than an old 2 or 3-lever lock. If you cannot find the markings or you are not sure, take a photo of the faceplate and the key and WhatsApp it to me, and I will tell you for free.
BS3621 vs TS007: what is the difference?
They are two different standards for two different door types, which is why the confusion costs people money. BS3621 is the British Standard for 5-lever mortice and rim locks on timber doors. TS007 is the BSI Kitemark scheme for euro-profile cylinders and the security handles around them, which is what protects a uPVC or composite door against lock snapping. Put simply: timber door, you want BS3621; uPVC or composite door, you want TS007 3-star (the cylinder rating) and PAS3621 for the mechanism. Some insurance wordings name one, some name the other, and some offer "BS3621 mortice OR TS007 3-star cylinder" as alternatives depending on the door. The mistake to avoid is paying for a full lock change to "make it British Standard" on a uPVC door, where a cylinder upgrade is all that is needed or possible.
What is the difference between a 3-lever and a 5-lever mortice lock?
The number of levers is the number of moving parts inside the lock that the key has to lift to the right height before the bolt will move, so more levers means more possible key combinations and more resistance to picking. A 3-lever mortice lock is fine for an internal door or a garage, but it is not secure enough for a final-exit door and it will not meet your insurance. A 5-lever mortice deadlock is the one insurers want on a timber front or back door, and when it carries the BSI Kitemark and the BS3621 stamp it is the British Standard lock the policy is asking for. If your timber door currently has a 3-lever lock, upgrading it to a BS3621 5-lever is usually a straightforward like-for-like swap.
How much does a BS3621 5-lever mortice lock cost fitted?
From £120 fitted for a like-for-like replacement, which covers my labour plus a Kitemarked BS3621 5-lever mortice deadlock (Union, ERA or Chubb, depending on the door). That assumes the door is already morticed for a lock of the same size, which most timber doors that already have a mortice lock are. If the door has never had a mortice lock and the pocket has to be cut fresh, that is more work and I will quote it separately once I have seen the door. No call-out fee, no VAT added, and I photograph the Kitemark stamp once it is in so you can email it straight to your insurer.
Does my insurer require window locks too?
Often, yes, and it is the clause people forget until a claim is turned down. A lot of UK home insurance policies require key-operated locks on all easily accessible windows, usually meaning ground-floor windows and any upstairs window that can be reached from a flat roof, porch or extension. The wording varies, so check your own schedule. If your windows have the little key-locking handles or espagnolette locks already, you are probably fine; if they are seized, missing keys, or were never fitted, that is a gap worth closing. I can check the windows at the same time as the door and sort any that are not working, quoted on the day once I have seen them.
Ready when you are
Insurance asking for BS3621? Get the honest answer on WhatsApp.
Send me a photo of your door and the lock, plus your postcode. I'll tell you whether you need a BS3621 mortice, a TS007 cylinder, or nothing at all, and what it would cost. No call-out fee. No deposit. No surprises.
Page last reviewed: . Reviewed by Sean Hamilton, the locksmith behind Lockerfella, under our editorial standards.