Types of Door Locks Explained: A Leeds Locksmith’s GuideEuro cylinders • mortice locks • uPVC mechanisms • night latches

Written by Radu Oprea, Locksmith Leeds MobileLS Ltd. Based on common lock types I work on across Leeds homes, flats and business premises. Last updated 20 June 2026.

Quick guide: which lock do I probably have?

If none of that quite matches what you are looking at, the sections below explain each lock type in more detail.

Euro cylinder locks

If you have a uPVC or composite front door, the visible key barrel you see from the outside is probably a euro cylinder. It is the part you actually put your key into.

A few things are worth knowing about euro cylinders:

• The cylinder is only one part of the lock setup.
• It works with the wider locking mechanism inside the door.
• Replacing the cylinder is not the same as replacing the full multipoint lock.
• Cylinders come in different lengths, measured in millimetres.
• A poorly fitted cylinder can stick out too far from the handle plate, which is not ideal for security.

I will usually suggest replacing a euro cylinder when:

• You have moved house and do not know who else has keys.
• Keys have been lost or stolen.
• A tenant has moved out and the locks have not been changed.
• The key spins, sticks, or feels gritty when turning.
• You want to upgrade to an anti-snap cylinder.
• The existing cylinder is old, basic, or poorly fitted.

A lot of the lock changes and security upgrades in Leeds I do are cylinder changes rather than full lock replacements.

If the mechanism is working properly and only the keys or cylinder security are the issue, a cylinder swap is often the right job.

Anti-snap locks and 3-star cylinders

Lock snapping is something many homeowners have heard of, even if they are not sure exactly what it means.

In simple terms, some older or basic euro cylinders can be snapped under force. If the cylinder breaks in the wrong place, it can expose the locking mechanism behind it.

Anti-snap locks are designed to resist this method of attack. They have a sacrificial section that is meant to break away in a controlled way, helping protect the working part of the cylinder.

Two security standards come up often when choosing a cylinder:

• TS007: this uses a star rating system. A 3-star cylinder is the highest individual cylinder rating under that standard.
• SS312 Diamond: another recognised high-security cylinder standard.

A 3-star cylinder is usually a sensible choice for a uPVC or composite front door. Some properties use a 1-star cylinder together with 2-star security handles or escutcheons to achieve a similar overall security level.

The important thing is not just the rating on the box. The cylinder also needs to be the correct size and fitted properly. A good cylinder fitted badly is like a strong gate left hanging on tired hinges.

I would avoid choosing a front door cylinder purely on price. No lock is impossible to break, and I would never claim that. What a properly fitted anti-snap cylinder does is make a common forced-entry method harder, slower and less attractive.

If you are not sure what your current cylinder is rated to, this is usually quick to check during a lock change in Leeds.

uPVC multipoint locking mechanisms

This is the part that confuses many customers, and it is where a lot of uPVC door problems actually come from.

The euro cylinder is the part you see. Behind it, running up and down the edge of the door, is the multipoint locking mechanism. This is sometimes called the multipoint lock, the strip, the gearbox, or the centre case.

The mechanism is what actually does the locking. Depending on the door, it may include:

• Hooks
• Rollers
• Mushroom cams
• A deadbolt
• A latch

The gearbox or centre case is often the part that fails first, especially on older doors or doors that have been forced for a while.

Door alignment also matters. A door that has dropped slightly, or hinges that have worn, can make a perfectly good lock feel broken. Sometimes the lock is not the real problem. The door is simply not sitting correctly against the frame.

Common symptoms include:

• The handle feels stiff or heavy to lift.
• The key is hard to turn.
• The door only locks if you lift the handle hard.
• The door opens fine but will not lock properly when closed.
• The key gets stuck halfway.
• The handle drops down on its own.
• The handle feels loose.
• The mechanism fails completely and the door will not lock.

If the handle has started feeling stiff, try not to keep forcing it. A stiff uPVC lock is often a warning sign before the gearbox fails completely. Catching it early can sometimes avoid a full lockout or a more expensive repair.

If any of this sounds familiar, it is worth looking at uPVC door lock repair before the mechanism fails completely.

Mortice locks

Mortice locks are most commonly found on wooden doors. You will see plenty of them on older Leeds houses, especially where the property still has timber front or back doors.

A mortice lock is fitted into a pocket cut directly into the door. It does not sit on the surface like a night latch. You will usually spot it by looking at the keyhole on the face of the door and the lock faceplate on the door edge.

For external wooden doors, a 5-lever mortice lock is a common recommendation. Five-lever locks generally offer better security than 2-lever or 3-lever locks, which are more often used internally.

A British Standard mortice lock will usually show a kite mark and BS 3621 marking on the faceplate. This is the type of marking insurers and landlords often expect to see on external wooden doors.

There are two main types:

• Sashlock: this has a latch operated by the handle and a deadbolt operated by the key. The latch holds the door closed, while the deadbolt locks it securely.
• Deadlock: this has only a deadbolt. There is no handle-operated latch. You use the key to lock and unlock it.

Whether you need lock repair in Leeds for an existing mortice lock, or a full lock change in Leeds to bring an older door up to a better standard, wooden door lock work is usually straightforward once the lock type is identified.

Night latches and Yale-style locks

Most customers call these “Yale locks”, and I know exactly what they mean. Yale is a brand name, but it has become the everyday name many people use for this style of lock.

A night latch is usually fitted to the inside surface of a wooden door. It is often paired with a smaller rim cylinder on the outside.

You will often see night latches on:

• Older wooden front doors
• Flat entrance doors
• Doors that self-lock when pulled shut
• Doors with a second mortice lock fitted lower down

The self-locking feature is useful, but it is also one of the main causes of lockouts. If the door closes and your keys are still inside, the latch has done exactly what it was designed to do. That does not make it any less annoying when you are standing outside.

Common night latch problems include:

• Locked out with keys left inside.
• Door slammed shut in the wind.
• Latch not retracting properly.
• Key turns but the latch does not open.
• Internal snib or button causing confusion.
• Old latch sticking or dragging.

If you are locked out of your house or flat because of a night latch, you are far from the only one. This is one of the most common lockout situations I see across Leeds.

Rim cylinders

The smaller cylinder fitted to the outside of a door with a night latch is called a rim cylinder.

It may look a little like a euro cylinder at a quick glance, but it is a different type of cylinder and it fits differently. Euro cylinders and rim cylinders are not interchangeable.

Rim cylinders are commonly replaced when:

• Keys have been lost.
• A tenant or previous occupant may still have keys.
• You have moved into a new property.
• The cylinder is worn or unreliable.
• The night latch is being replaced or upgraded.

Replacing a rim cylinder is usually a smaller job than replacing a full uPVC multipoint mechanism, because you are dealing with the cylinder rather than a long locking strip inside the door.

Thumbturn locks

A thumbturn is a small knob or lever fitted on the inside of a cylinder. It allows the door to be locked or unlocked from the inside without using a key.

Thumbturns can be useful for:

• Quick exit in an emergency.
• Day-to-day convenience.
• Flats and rental properties.
• Doors used by children, elderly people, or anyone who may struggle with keys.
• Situations where a key should not be needed to get out from inside.

You will often see thumbturns on flats, newer composite doors and some rental properties.

They do need to be chosen carefully. A thumbturn can be useful from a fire escape point of view, but the right setup depends on the door, the property and the security needs.

I cannot give legal advice, but landlords and property managers should always consider fire safety guidance, insurance requirements and the type of door before deciding what lock setup is suitable.

Garage, gate and shed locks

It is not just front doors that need locksmith work. Garages, gates and sheds often have their own lock problems.

Common outbuilding locks include:

• Padlocks
• Garage door locks
• Shed locks
• Hasp and staple setups
• Gate locks
• Basic mechanical locks that have worn or rusted

These jobs are usually simpler than front door lock repairs, but they are still worth doing properly, especially if the shed or garage contains tools, bikes or work equipment.

A cheap padlock on weak fittings will not protect much. The lock, hasp, screws and door material all matter. Security is only as strong as the weakest part of the setup.

Which lock is best for my front door?

The best lock depends on the door, but here is how I usually think about it.

For a uPVC door, you normally want a correctly sized euro cylinder, ideally anti-snap rated, working with a multipoint mechanism that is properly adjusted. A good cylinder fitted to a failing mechanism will not solve the whole problem.

For a composite door, the principle is similar. A high-security cylinder is a good start, but the mechanism, keeps, handles and alignment also need to be right.

For a wooden door, a British Standard 5-lever mortice lock is often the right choice for external doors. Some wooden doors also have a night latch for everyday use, with the mortice lock used for the main security.

For a rental property, changing locks after a tenant changeover is usually sensible. It gives the landlord or new tenant a clean start with fresh keys.

After a burglary or attempted break-in, it is not just the cylinder that needs checking. The handle, keeps, frame, multipoint strip, latch, door alignment and surrounding damage may all need looking at before the door can be considered secure again.

After moving house, changing the locks is a simple precaution. You do not know how many sets of keys may still be with previous owners, tenants, tradespeople, neighbours, family members or estate agents.

If you want an idea of likely cost, my locksmith prices page gives a general guide. For an accurate quote, I usually need to know the door type, lock type and what problem you are having.

Repair or replace: how do I know?

This is one of the most common questions I get asked.

The honest answer is: it depends what is actually wrong.

A lock may be repairable if:

• The door has dropped or become misaligned.
• The handle has come loose.
• The gearbox can be replaced.
• The cylinder is fine but the mechanism needs adjustment.
• The keeps need adjusting.
• The door works when open but not when closed.

A lock should usually be replaced if:

• Keys have been lost or stolen.
• The lock was damaged during a burglary or attempted break-in.
• The existing cylinder is poor quality or unrated.
• The mechanism has failed completely.
• You have moved house.
• A tenant has moved out.
• You want a higher level of security than the current lock provides.

I will always tell you which category your lock falls into before doing the work. Sometimes a small adjustment or part replacement fixes a problem that looked much more serious than it was.

What photos help me identify your lock?

If you are not sure what lock you have, a few clear photos can help a lot.

The most useful photos are:

• A photo of the outside handle and key area.
• A photo of the inside handle or thumbturn, if there is one.
• A photo of the door edge where the latch, hooks or bolts come out.
• A photo showing whether the door is uPVC, composite or wooden.
• A photo of any visible markings on the lock faceplate.

Try to take the photos in good light and not too close to the lock. A slightly wider photo often helps more than a blurry close-up.

You can send photos by WhatsApp if that is easier. In many cases, I can identify the lock type and explain the likely options before visiting.

Common lock problems I see around Leeds

A few patterns come up again and again across the city.

In student areas such as Headingley and Hyde Park, locks often see heavy use and frequent tenant changeovers. Keys get copied, lost, handed around, or left behind.

In older areas such as Roundhay, Chapel Allerton and Meanwood, wooden doors with mortice locks and night latches are still common. Some are perfectly serviceable, while others are worn, loose, or below the standard the customer wants.

Across Leeds suburbs, uPVC and composite doors are very common. On these doors, stiff handles, worn gearboxes and misaligned multipoint mechanisms are some of the most regular problems I see.

Landlord and tenant changeovers are another common reason for lock changes. Even when everything has ended politely, fresh keys remove uncertainty.

Post-burglary repairs are different. In those cases, the job is not just about replacing a lock. The whole door setup needs checking so the property can be made secure again.

Sometimes, though, there is no dramatic reason. A lock has simply worn out after years of daily use. Keys, springs, latches, gearboxes and handles all have a working life.

Need help identifying your lock?

If you are still not sure what lock you have, that is fine. It is usually easier for me to look at a photo than for most people to describe the lock over the phone.

Send a clear photo of the door, handle and key area, or call me directly. I can usually identify the lock type and explain the likely options before visiting.