BS3621 locks, supplied and fitted to insurance spec.
Most UK home insurance policies require BS3621-marked locks on final exit doors. We supply, fit, and provide written certification for your insurer.
BS3621 mortice locks — what they are and whether you actually need one.
BS3621 is the British Standard for security mortice deadlocks. A lock with this kite mark has been independently tested to resist specific attack methods: picking, drilling, sawing, and manipulation. It’s the lock type that most home insurance policies require on the main front door as a condition of cover.
A 5-lever mortice lock sits inside the door itself, embedded in the wood rather than bolted onto the surface. It’s inherently more robust than a rim lock or a cylinder-only setup. The 5-lever part refers to the number of levers inside the case — more levers mean a more complex key and harder to pick. BS3621 5-lever locks are the standard on UK timber front doors and have been for decades.
There’s a common confusion between a mortice lock and a cylinder lock. Many UPVC doors use cylinders without a mortice, which is fine — but if your front door is timber and older than 15 years, there’s a reasonable chance the existing mortice doesn’t meet BS3621, especially if the property hasn’t had a lock upgrade. We can check and confirm before recommending a replacement.
Fitting a BS3621 to an existing door takes 45-75 minutes for a straight swap. If the existing lock pocket is the wrong size for the replacement body, it takes longer. We’ll tell you up front if that’s the case.
Why customers choose us
- ✓We check your current lock first
We’ll confirm whether your existing mortice meets BS3621 before recommending a replacement. Sometimes it already does.
- ✓Insurance documentation provided
We can issue a receipt and installation note confirming your new lock meets BS3621 — useful for your insurer.
- ✓British Standard locks in stock
Yale, Chubb, Union and ERA British Standard 5-lever mortice locks carried on the van for most standard door sizes.
- ✓Combined with anti-snap cylinder
We can pair a BS3621 mortice with an anti-snap cylinder at the same visit for full door security.
- ✓12-month warranty on all parts
On everything we fit. If anything fails within 12 months, we return at no charge.
Seven things, done properly.
One call, one fixed price, one engineer.
Call us
Real person picks up in under 8 seconds. We confirm your job, postcode, and quote on the phone — in writing on text if you’d like.
Engineer dispatched
Closest DBS-checked engineer in your area heads to you. Live ETA on text. Average arrival 20 minutes.
Job done
Quoted price is the price you pay. Card or cash. 12-month warranty on every part fitted.
Follow-up
Free door re-adjustment within 14 days if anything’s not right. Receipt and cert by email.
Real jobs. Real results.
Photos from our engineers — every job documented, every time.
The 3 questions everyone asks
How fast can you arrive?
Average 20 minutes in your area. 24/7, including bank holidays.
What’s the cost?
From £85 + parts. Fixed price confirmed before any work starts. No hidden charges.
Will you damage my door?
Non-destructive entry on 9 of 10 doors. We open without damage whenever possible — drilling is a last resort, with your consent first.
About british standard locks.
What customers say.
4.9 stars from 2,847 verified reviews.
“Insurer required a BS3621 deadlock. Fitted and certified same day. Insurance claim approved without question.”
“Three-star TS007 cylinder fitted throughout the house. Engineer knew exactly which spec my insurer needed.”
“Written certificate provided, engineer professional. Finally feel secure — excellent service.”
Nationwide, with engineers in your postcode.
142 DBS-checked engineers across England, Wales, and Scotland. Most jobs covered within 30 minutes of your call.