If you ask a police officer or home security expert what lock you should have on your front door, the answer is almost always the same: a five-lever mortice lock that meets British Standard BS3621. But why is this particular lock so highly recommended? This article explains everything you need to know.
What Is a Five-Lever Mortice Lock?
A mortice lock is fitted into a recess cut into the edge of a door. A five-lever mortice lock has five levers inside the mechanism — each lever must be lifted to the correct height by the key before the bolt can be thrown. This makes the lock significantly more resistant to picking than simpler two or three-lever locks.
What Is British Standard BS3621?
BS3621 is the British Standard for thief-resistant locks. To achieve this certification, a lock must pass rigorous tests for resistance to picking, drilling, and other forms of attack. A BS3621 lock must also have a minimum of 1,000 key differs (unique key combinations) to prevent key duplication.
Why Police Recommend Five-Lever BS3621 Locks
Resistance to Picking
Five levers make the lock significantly harder to pick than two or three-lever alternatives. A skilled lockpick can open a two-lever lock in seconds; a five-lever BS3621 lock requires much more time and skill.
Resistance to Drilling
BS3621 locks must include hardened steel components that resist drilling attacks. Many burglars use drills to destroy lock mechanisms — a BS3621 lock is designed to withstand this.
Insurance Requirements
Most home insurance policies require external doors to be fitted with a BS3621 lock. Failing to meet this requirement can invalidate your insurance in the event of a break-in.
Secured by Design
The police-backed Secured by Design initiative recommends BS3621 locks as part of its guidelines for home security. Properties that meet Secured by Design standards are statistically less likely to be burgled.
Choosing the Right Five-Lever Lock
Not all five-lever mortice locks are equal. Always look for the BS3621 kite mark on the lock body. Keys4U stocks a wide range of British Standard locks from leading manufacturers and can advise on the best option for your door.
For professional lock installation across London and the UK, call Keys4U on 033 3305 2993.
