Door Lock Types Explained: Euro, Mortice & Multipoint

Walk into any hardware shop and the choice of door locks can be bewildering. This plain-English guide explains the main lock types found on UK homes, how each works, and the security standards worth looking for when you upgrade.

Euro cylinder locks

The Euro cylinder is the long, key-operated barrel you will find in most uPVC and composite doors, usually paired with a multipoint mechanism. Its big weakness, historically, was lock snapping — criminals snapping the cylinder to defeat it. Modern anti-snap cylinders solve this by having a sacrificial section that breaks away while leaving the lock secure.

• Look for the TS007 3-star kitemark, or a 1-star cylinder paired with 2-star security handles.
• Better still, choose a SS312 Diamond-rated cylinder, which is tested against snapping, picking, drilling, and bumping.
• Always have the cylinder sized correctly — one that protrudes from the handle is much easier to attack.

Mortice locks

A mortice lock sits within a pocket cut into the edge of the door itself, common on timber doors. There are two main kinds: a mortice deadlock (key only, no handle) and a sashlock (combines a deadbolt with a latch and handles).

For insurance and real security, look for a five-lever BS3621 mortice lock on final exit doors. The BS3621 kitemark tells your insurer the lock meets a recognised British Standard for resistance to forced and manipulative attack.

Nightlatches

The classic nightlatch (often called by the common brand name) is the rim lock fitted to the surface on the inside of the door, with a snib to hold it back. A standard nightlatch latches automatically when the door closes but is not, on its own, enough security for a front door. A BS3621 deadlocking nightlatch that can be locked from outside and dead-locked from inside is far stronger and is what insurers usually want to see.

Multipoint locks

Multipoint mechanisms are the systems in uPVC and composite doors that throw several locking points — hooks, rollers, or bolts — up and down the door frame when you lift the handle and turn the key. They spread the load and make the door much harder to force. The heart of the system is the gearbox; when a uPVC door feels stiff or the handle drops, the gearbox is often failing. If yours is sticking or jammed, we cover uPVC door repairs including multipoint gearbox replacement.

What about Adams Rite locks?

You will often see Adams Rite-style locks on aluminium commercial and shopfront doors. These narrow-stile mechanisms suit slim frames and can be fitted with a high-security Euro cylinder for added protection.

Which lock is right for you?

1. uPVC or composite door: multipoint mechanism with an anti-snap TS007 3-star or SS312 Diamond Euro cylinder.
2. Timber front door: a BS3621 five-lever mortice deadlock, often alongside a deadlocking nightlatch.
3. Back or secondary doors: at minimum a BS3621-rated lock so the whole property is covered.

If you are unsure what you have or want to bring everything up to insurance standard, professional lock replacement and installation takes the guesswork out of it.

MrSpeedy Locksmith fits insurance-approved locks across Birmingham and is happy to advise on the right standard for each of your doors.