Door Lock Types

Traditionally, in the UK, the most popular locks are mortice locks and night latches. These are relatively simple locks that are easy to fit to doors made of timber. They can either be attached to the surface of a door or fitted into a morticed slot created on the door’s edge.

They also offer a good level of security, particularly when used together.  

The advent of uPVC doors, however, has also made key operated multi-point locking systems very popular in the UK. These are more complicated locks that fit into the edge of a uPVC door. These uPVC door lock types can also offer a very high level of security. They often work in conjunction with a Euro cylinder lock. 

While these three lock types are most popular in the UK, in some situations it will make sense to use a traditional bolt, a push button lock, a smart lock, a padlock or another type of lock. Cylinder locks (including Euro cylinder locks) are also often used in conjunction with another locking mechanism. 

British Standard BS3621 compliant locks

Some insurance companies require front and back door locks to be compliant with British Standard BS3621. This means they’ve been tested against burglary methods such as drilling and picking.

It’s a good idea to consider whether you need your lock to be BS3621 compliant before you purchase it. You can also check your existing locks to see if they are compliant. BS3621 compliant locks will have a British Standard kitemark and a number starting with BS3621 engraved on the faceplate. For more information see the UK building security regulations. 

In this section, we’ll look at the most common door locks used in the UK. We’ll look at how they function and where each type is normally used.

5 lever mortice deadlock

5 lever mortice deadlocks are a very common type of mortice lock in the UK. Mortice locks are fitted within the body of the door, into a morticed slot at its edge. A key can be inserted into the locking mechanism from either side of the door to lock and unlock the bolt. When the lock is turned, the bolt will extend from the lock into a housing on the door frame, locking the door.

Mortice locks are common in doors made of timber. They’re not generally found on uPVC doors or doors made from aluminium or composite material. The most common use case is on the front or rear doors of people’s homes.

You might need to check whether a mortice lock is BS3621 compliant before you buy it. You should look for the British Standard kitemark and the number BS3621 on the lock’s faceplate before you make a purchase if you need one that is compliant.   

• 3 and 5 lever mortice locks: Mortice locks can be 3 or 5 lever types, and this refers to the number of levers in the locking system. In a 3 lever mortice lock, the key engages three levers as it’s turned. In a 5 lever mortice lock, it engages five levers as it’s turned. There is less risk of key duplication and lock picking with a 5 lever lock because the extra levers provide additional security. 3 lever locks are not BS3621 approved because they are less secure. If a lock is 5 lever, this will normally be engraved on its faceplate.
• Deadlock and sash lock mortice locks: Mortice locks can be either deadlock or sash lock types. Mortice deadlocks feature only a deadlock that is operated with a key. To close a door with a mortice deadlock, the lock has to be engaged with the key. Sash lock types, on the other hand, feature an additional latch that is operated with a handle. Having this latch means the door will be automatically held closed when the door closes.  

Key operated multi-point locking system

Key operated multi-point locking systems are the most common lock for uPVC doors. They can also be found in composite doors, aluminium doors and, nowadays, even in doors made of timber.  

With this locking mechanism, a cylinder lock operated by a single key is used to engage at least three (normally five) separate locking points at different locations in the door’s frame. Normally, the handle is pulled upwards and the key is turned in the locking mechanism to engage all the locking points.

Key operated multi-point locking systems are commonly found on domestic property external doors in the UK. They work perfectly well for both front and rear doors. They can be found on commercial properties as well.

The big advantage with multi-point locking mechanisms is that the door is much harder to force open because of the additional locking points. As well as this, having a cylinder lock means the key can be made to match with other doors at a property that also have cylinder locks.

Night latch with key-locking handle

Night latches with a key-locking handle feature a deadlatch that is mounted to the inner surface of the door. On the external surface of the door, a key-locking handle is then fitted with a rim cylinder lock for opening with a key.

If a door with this type of lock is closed, the deadlatch will automatically latch the door shut, unless the mechanism is ‘kept on the latch’. Being ‘on the latch’ means that the latch mechanism has been disengaged with a lever operated from the inside. A key is needed to open a night latch from the outside when it is locked.

These locks are very simple, and the automatic locking system reduces the chances of a door being left unlocked by mistake.   

Night latches are often used in conjunction with a mortice lock to increase security. In some cases, night latches feature additional security measures that make it harder to break into doors from the outside. 

Night latches are often used on external domestic property doors or on internal doors of domestic or commercial properties. They are also often found on glass panelled doors. When it comes to using them on external doors, it’s worth noting that they should be avoided on doors with letter boxes or cat flaps. This is because it may be possible to unlock the mechanism from the outside by reaching through with wires or another makeshift opener. 

Night latches are also referred to as rim automatic deadlatches and Yale locks. Terminology can become confusing. The terms are also used to refer to different variations of deadlatch. There are also more types of Yale door locks than just night latches.

Cylinder locks

Cylinder locks are locking mechanisms that operate in conjunction with other locking mechanisms. They are often used with multi-point locking systems in uPVC doors, for example. In this situation, they control the locking and unlocking of the multiple locking points on the door.

Another type of cylinder lock, rim cylinder locks, are also found in use with night latches. Cylinder locks of other types are also used on other door lock types.

Advanced rim cylinder locks come with anti-snap, anti-pick and anti-drilling features that make them more secure. You can pick a British Standard BS3621 compliant cylinder lock for a high level of security. 

Euro cylinder locks are a type of cylinder lock. These can be either single cylinder or double cylinder.

Door bolts

Door bolts are a simple door lock type that most people are familiar with. A sliding bolt is slid into a locking mechanism to lock a door.

Bolts are normally surface mounted, but they can also be morticed inside a door. They can also be key or code controlled rather than just being manually controlled. Usually, door bolts are only used by themselves on internal doors. On external doors, they are often used in conjunction with another key operated locking mechanism.

The big disadvantage with bolts is that they can usually only be opened and closed from the inside of the door.

Nowadays, door bolts are often used for internal doors on domestic properties. Bathroom doors are a common use case. They can, however, be added to external doors or used on commercial properties.

Push button locks

Push button locks can be mechanical or electronic, and they are used for keyless lock operation. Often, they’re fitted where doors are used by a large number of people. 

With these locks, a push button mechanism is mounted onto the external surface of the door. After the correct code is entered, a lever on this external mechanism is turned to operate a locking mechanism that is usually morticed inside the frame of the door. The advantage is that no key is required for operation, which is impractical for some buildings. 

Push button locks can be used for internal doors that do not require heavy security. As well as this, however, heavier duty external-use push button locks are available.    

Push button locks are commonly found on properties like schools, offices and industrial buildings.

Smart door locks

Smart locks are similar to push button locks. An external smart reader is attached to the surface of the door. This then links to a locking mechanism that can be either morticed inside the door or attached to the external surface of the door.

Smart locks are often chosen for residential properties and hotels that are accessed by a large number of people. Public libraries, university buildings or medical facilities are all locations where a smart lock might be used.

The advantage of smart locks is that there is a high level of control over locking and unlocking doors.