The main types of door locks in UK homes are mortice locks, cylinder locks (including the euro cylinder), night latches, multi point locks and smart locks. Mortice locks and 5 lever mortice deadlocks suit timber doors; cylinder and multi point locks suit uPVC, composite and aluminium doors; and smart locks add keyless entry.
There are more types of door locks in a typical UK home than most people realise, and knowing the different types of door locks makes it far easier to secure your home. This guide explains every one of the common door lock types: the door locks on your front door, your internal doors and your exterior doors, plus how each locking system works, and which door locks suit timber, uPVC, composite and aluminium doors. Different locks suit different doors, so understanding these types of door locks helps you choose a secure lock with confidence, or know exactly what to ask for when you need one fitted.
We’ll cover all the main types of door locks in turn, with the lock types grouped by how they work and by door material, and we link out to pages where we can supply and fit each lock.
Door Locks: The Basics
Almost every lock on a UK door belongs to one of a few families of door locks. The main types of door locks are mortice locks, cylinder locks (including the euro cylinder), night latches, and the multi point locking systems built into most modern doors. Smart locks are a newer type of door lock. These door locks each work through different locking mechanisms, and each offers different security features.
Whatever the type, good door locks all try to do the same job: resist forced entry, resist lock picking and lock bumping, and give smooth operation every day. The strongest door locks pair a good mechanism with proper installation into a solid door and door frame. Even high security door locks are only as good as the door they sit in, and a weak entry point undoes an expensive lock. With that in mind, here are the door lock types you’ll meet, and the security features that separate a basic lock from a secure lock.
Door Lock Types at a Glance
These are the common door lock types found on UK doors, and where each of these door lock types is normally used:
- Mortice locks: set into the edge of timber doors; the 5 lever mortice deadlock is the British Standard front-door workhorse.
- Cylinder locks: euro cylinder and rim cylinder locks that carry the key, used on uPVC, composite and wooden doors.
- Night latches: surface mounted locks (the classic Yale-style latch, often called Yale locks) fitted to the face of the door.
- Multi point locks: the multi point locking systems inside uPVC and composite that throw multiple bolts into the frame.
- Smart locks: electronic and keyless door locks with keypad or app control.
Learn these lock types and the rest is easy, because every specific lock is a variation on one of these door lock types. Even the door handle you touch is part of the system on many doors. Below we take each of these types of door locks in turn, so you can match the right lock types to your own doors.
Here is how the main door lock types compare at a glance:
| Lock type | Best for | Security level | Insurer-approved? |
|---|---|---|---|
| 5 lever mortice deadlock | Timber and wooden doors | High | Yes, to BS3621 |
| Euro cylinder | uPVC, composite and aluminium doors | Low to high (fit anti-snap) | Yes, when anti-snap rated |
| Night latch (rim automatic deadlatch) | Timber front doors, as a second lock | Medium to high | Yes, when BS3621 rated |
| Multi point locking system | uPVC and composite doors | High | Usually, with a rated cylinder |
| Smart lock | Keyless entry on most doors | Varies by model | Only with a rated cylinder underneath |
Mortice Locks
Mortice locks are cut into a pocket in the edge of the door, so the body of the lock hides inside the door. They are the traditional door locks for timber doors and any wooden door front door, and they come in two forms: the sashlock, with a latch and deadbolt worked by a handle and key, and the deadlock, with a deadbolt only. Because the mechanism is buried in the door, mortice locks resist break-ins well.
The security of mortice locks is set by the number of levers. A 3 lever lock is fine for internal doors, but external doors need a 5 lever mortice lock. Lever locks are graded on how many tumblers must line up before the bolt moves, so a 5 lever mortice is far harder to pick than cheaper lever locks. The 5 lever mortice deadlock is the classic external-door choice, and we’ll come back to it below. If your timber door still wears an old low-lever lock, moving up to a 5 lever mortice is one of the simplest ways to add security. We can supply and fit mortice locks and sashlocks on any wooden door.
Cylinder Locks
Cylinder locks hold the key mechanism in a removable barrel (the cylinder) that drives the bolt when the key is inserted and turned. This is the most common family of door locks on modern doors, because euro cylinder locks and rim cylinder locks are quick to fit, which makes changing these locks easy. The two you’ll meet most are the euro cylinder, used in the multi point locking systems of uPVC and composite, and the rim cylinder, which sits behind a night latch.
Cylinder locks come as single cylinder (key one side, thumb turn the other) or double cylinder (key both sides). Double cylinder deadbolts give extra security on a door near glass, because there’s no thumb turn to reach, though a single cylinder with a thumb turn is often safer for escape. You can also have cylinder locks keyed alike, so one key works several doors. The weak point of older cylinder locks is snapping, so anti-snap cylinder locks are a worthwhile upgrade. We change euro cylinder locks and rim cylinder locks for anti-snap versions on the spot.
How a Locking System Works
Every lock is really a small locking system: a mechanism, a bolt or bolts, and a strike plate in the door frame that the bolts drop into. A simple locking system throws a single bolt; a multi point locking system throws several bolts at multiple locking points up and down the door. The more locking points, the more evenly the door is pulled into the frame, and the harder it is to force. Systems with multiple points give controlled access at every part of the door edge, not just the middle.
The strength of any locking system depends as much on the frame as the lock. Multiple bolts into a flimsy keep still tear out, which is why proper installation matters: the lock’s faceplate must sit flush, the bolts must meet the locking points, and the strike plate must bite into solid timber. Other locking mechanisms add security elsewhere: a sliding bolt or surface bolt and hinge bolts protect the hinge side, and these other locking mechanisms are cheap extra security. Set up well, a locking system gives both smooth operation and resistance at every entry point. For multi point locks that no longer line up, the fix is adjustment or a new mechanism, not a new door.
Key Locking Handle
On most uPVC and composite doors the multi point locking system is worked by a key locking handle: lift the handle to throw the bolts, then turn the key to lock them. A key locking handle is convenient and secure, because the door genuinely engages multiple locking points rather than one bolt. The cylinder inside the handle set is what the key turns, so a key locking handle is only as strong as that cylinder. An anti-snap euro cylinder behind the handle is essential.
If your key locking handle has gone stiff, or the door only locks when you lift the handle hard, the multi point mechanism is wearing out and should be serviced before it fails. A jamming key locking handle is one of the most common faults we repair on uPVC and composite doors.
Night Latches
Night latches are the surface mounted locks fixed to the inside face of the door, with the familiar snib (the classic Yale locks pattern). Unlike mortice locks, night latches aren’t set into the door, which makes them easy to fit and a popular second lock above a mortice deadlock. A standard night latch locks automatically when the door shuts (the rim automatic deadlatch), so the door is latched behind you with no key.
Two grades matter. A basic night latch can be slipped by some attacks, while a rated rim automatic deadlatch deadlocks the latch and resists forced entry far better. Many UK front doors run two locks: a British Standard rim automatic deadlatch on top and a 5 lever mortice deadlock below, so an intruder faces a double lock of two separate mechanisms. The button locks on night latches let you hold the latch open or deadlock it from inside. We supply and fit night latches and rim locks in standard and British Standard grades, and can add an additional lock where you only have one. Ask about a rim automatic deadlatch to replace a tired basic night latch, and about rim locks for a second point of security.
Lock Types by Door and Material
The right lock types depend on your door type, because a lock that suits a timber door may not fit a uPVC one. Here’s how the lock types map to the doors in a typical home:
- Timber and wooden door front door: a 5 lever mortice deadlock plus a night latch; the insurer-friendly setup for external doors and exterior doors generally.
- uPVC door and composite doors: a multi point locking system with a euro cylinder and a key locking handle.
- Aluminium doors: usually a hook-bolt multi point locking system with a euro cylinder.
- Glass panelled doors: double cylinder deadbolts, or a lock with no thumb turn by the glass, so a broken pane gives no access. This is where a double cylinder lock earns its place.
- Internal doors and interior doors: light-duty locks, tubular latches or privacy button locks; security is rarely the point indoors.
Front door and external doors always deserve the strongest lock types you can fit; internal doors and interior doors can use simpler locks. Smart locks are increasingly common on the front door too. A smart lock adds keyless door locks convenience with keypad or app entry, and many smart door locks fit over or replace an existing euro cylinder or night latch. Smart locks and electronic locks vary in quality, so choose smart door locks with a good cylinder underneath and a power supply backup; the best smart locks keep a mechanical key override. Smart locks aside, matching the right lock types to your door material is the foundation, and we can fit any of them.
uPVC Door Locks
The uPVC door is the most common external door in the UK, and it almost always uses a multi point locking system driven by a key locking handle and a euro cylinder. Lift the handle on a uPVC door and the multi point locks throw their bolts (hooks, rollers and deadbolts) into the frame at several locking points, which is why a healthy uPVC door feels so solid. uPVC and composite doors share the same basic locking system.
Two things go wrong with a uPVC door. First, the multi point mechanism wears, so the handle stiffens and the bolts stop engaging, and a repair or new gearbox fixes it. Second, the euro cylinder is open to lock snapping, so an anti-snap cylinder is the best uPVC upgrade for enhanced security. If your uPVC door only locks when you fight the handle, don’t wait for it to lock you out. Book a uPVC repair before the locking system fails.
Euro Cylinder
The euro cylinder is the standardised barrel at the heart of most uPVC, composite and aluminium door locks. Because it’s a standard size, a euro cylinder is easy to change: good for you when you move in, and the reason euro cylinder locks are the main target of lock snapping. An attacker snaps the cylinder at its centre; a cheap one can be snapped in seconds.
The answer is an anti-snap euro cylinder with a Kitemark and the SS312 Diamond or three-star rating, engineered to break at a sacrificial line and leave the mechanism intact. You can have euro cylinder locks keyed alike so one key works front and back. A single cylinder has a thumb turn inside; where there’s glass nearby, a double cylinder removes the thumb turn for added security and maximum security against a reach-through. Upgrading a builder-grade euro cylinder to a high security one is inexpensive, so we carry anti-snap euro cylinder locks on the van.
Mortice Deadlock
A mortice deadlock is a mortice lock with a deadbolt only: no latch, no handle, just a bolt thrown with the key inserted and turned. It’s the classic second lock on a timber front door, fitted below a night latch, and the mortice deadlock is what most insurers mean when they specify a deadlock. A 5 lever mortice deadlock throws a solid bolt deep into the frame and can’t be pushed back once deadlocked, so this mortice deadlock resists forced entry and gives real security.
Not every mortice deadlock is equal. A 3 lever mortice deadlock suits internal doors, but external doors need a 5 lever mortice deadlock, and only a 5 lever mortice deadlock to BS3621 satisfies most home insurance. The bolt on a good mortice deadlock has hardened rollers to resist sawing, and the 5 lever mortice mechanism resists picking. If your timber door has an old two or three lever mortice deadlock, upgrading to a 5 lever mortice deadlock is the single best move. A proper 5 lever mortice deadlock is what turns a front door lock from token to genuine. We fit a British Standard 5 lever mortice deadlock on any timber front door lock setup, replacing a weak front door lock with a rated one.
Button Locks
Button locks are the small snib buttons on night latches that control the latch from inside: press one and the latch is held back so the door won’t lock; press the other and the latch is deadlocked so it can’t be slipped. On privacy sets for internal doors, button locks are the simple push-button that locks a bathroom or bedroom without a key.
Button locks are about control and convenience, not high security. They’re no substitute for a deadbolt on an external door. But the deadlocking button locks on a rated night latch add a useful layer, stopping the common trick where a latch is slipped with a card. Use the button locks to deadlock the night latch overnight, and rely on your mortice deadlock and euro cylinder for the heavy work. As additional security features go, button locks are simple but effective, and among the extra security features worth using every night.
British Standard
British Standard is the phrase to look for on any lock guarding an external door, because it’s what home insurers require and what genuinely resists attack. The key standard is BS3621, and a British Standard lock carries the BS3621 Kitemark on the faceplate. Both a 5 lever mortice deadlock and a rim automatic deadlatch can meet British Standard.
Fitting British Standard locks does two things: it gives maximum security against forced entry, lock picking, lock bumping and lock snapping, and it keeps your home insurance valid, since a claim can be refused if your external doors weren’t fitted to British Standard. Not sure yours qualify? Check the faceplate for the Kitemark; if it isn’t there, treat an upgrade as a priority. We only fit insurance-approved, British Standard locks on external doors.
Choosing Between the Types of Door Locks
With so many types of door locks to weigh up, the right choice comes down to your doors. On a timber front door, the strongest types of door locks remain a 5 lever mortice deadlock plus a night latch with rim locks. On a uPVC door, the door locks that matter are the multi point locks and the cylinder; these multi point locks lock the door into the frame, and those multi point locks are part of the multi point locking systems fitted to modern doors, the same multi point locking systems you’ll find on composite and aluminium doors. Homeowners comparing different types of door locks often ask about smart locks: smart locks and keyless entry are convenient, but they sit on top of the same door locks, so the underlying door locks still need to be strong. Understanding the types of door locks this way makes it simple: external door locks deserve rated door locks, internal door locks can stay simple, and the best types of door locks are those matched to your door. If you’re unsure which types of door locks or which multi point locking systems suit your home, we can advise on the door locks and door lock types that fit your doors, and fit whichever of these types of door locks you choose.
Frequently Asked Questions
Which door lock is most secure?
For a timber door, the most secure setup is a British Standard 5 lever mortice deadlock paired with a night latch. For a uPVC door, a multi point locking system with an anti-snap euro cylinder gives the best security. No single lock is most secure on its own; the strongest door locks combine a rated mechanism with proper installation into a solid frame.
What locks do insurers require?
Most UK home insurers require British Standard locks on external doors, which means BS3621. On a timber door that is a 5 lever mortice deadlock; on a uPVC door it is an anti-snap cylinder to the relevant standard. Check the faceplate for the BS3621 kitemark, and if it is missing, treat an upgrade as a priority.
What is lock snapping and how do I prevent it?
Lock snapping is an attack where an intruder snaps a euro cylinder in two to reach the mechanism, and it is the most common way uPVC doors are forced. Prevent it by fitting an anti-snap, three-star or SS312 Diamond cylinder in place of a standard one.
Can I fit a smart lock to any door?
Most smart locks fit over or replace an existing cylinder or night latch, so they suit uPVC, composite and timber doors, but always check the model against your door. Choose smart door locks with a rated cylinder underneath and a mechanical key backup in case the power supply fails.
How many types of door locks are there?
There are five main types of door locks in UK homes: mortice locks, cylinder locks, night latches, multi-point locks and smart locks. Every specific lock, from a sashlock to a rim cylinder, is a variation on one of these door lock types.
Need any of these door locks supplied and fitted? SW Locksmith covers South West London 24/7, from a lock change or upgrade to a full lock installation. Serving Battersea, Richmond and all SW postcodes. Call 07383010010.
