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Locksmith FAQ

Locksmith Woking FAQ: Lock changes and Insurance approved locks.

What are British Standard Locks?

Most insurance providers will require that locks meet a certain criterion prior to giving cover. Locks that conform to British Standard will carry a British Standards Institute (BSI) Kitemark, which acts as certification that the lock has been tested against certain benchmarks for its intended use as a theft resistant lock. This kitemark is engraved onto the lock and can usually be found upon the faceplate. There are three main types of BS Locks:

  • BS3621 locks are the most popular British Standard lock. To meet the British Standard, these locks are tested against levels of resistance, attack, and lock tampering. They are installed on ground floor external doors that are deemed vulnerable to attempted break in such as front and back doors of a domestic house.
  • BS8621 locks are found on non-ground floor level doors such as flats. Similarly, to BS3621 these locks are tested against levels of resistance, attack, and lock tampering. BS8621 compliant locks are operated by key entry and exit by thumb turn. This is due to the requirement of the British Standard, that the door can be used as a method of emergency escape, ensuring that people can exit the property quickly without needing a key. This is particularly important in the case of a hazardous situation where people need to evacuate immediately, such as a fire.
  • BS10621 is the standard given to locks that are operated by a key but can only be locked from the outside. These types of lock are often found on commercial properties as they enable a building to be locked down, preventing an intruder who gains access to the building through other means, from being able to exit through the door.

Alternatives to BS locks may be an anti-snap lock.


These are high security euro cylinders that are designed and tested to protect against lock snapping. When an intruder attempts to break the lock, the cylinder will snap and stay in the locked position, preventing entry from being gained. However, this is only the case if the Euro cylinder is approved to SS312 Diamond or TS007 3-star standards. This type of cylinder is normally found on UPVC doors.

  • Sold Secure (SS312) Diamond approved cylinders were the first test standard to oppose lock snapping, as such it is deemed the highest level of approval for cylinders. There are currently 15 different lock cylinders that are diamond approved.
  • TS007 euro cylinders are BSI kitemarked showing that they have been tested by a third party rather than being approved by the recommendations of the manufacturer. Additionally, they also carry a star rating. The minimum criteria for protecting against lock snapping is three stars. This information can be found on the cylinder.
    • 1 STAR - found on cylinders that have basic approval and have not been tested for snapping
    • 2 STAR - found on door furniture such as handles, escutcheons etc.
    • 3 STAR - found on cylinders that are tested for resistance against snapping
    • 1-star kitemarked cylinder with 2 star kitemarked door furniture can be used as an alternative to the 3-star euro cylinder option

Can I change my own locks?

Many customers are tempted to try and replace their locks themselves, but using the wrong lock type or size could leave your property at a higher risk of burglary. Whether you've moved, lost your keys, or wish to upgrade your locks to meet insurance approval, our experienced locksmiths can provide the professional services you need for peace of mind. Trust our Woking Locksmith's to keep your property safe and secure.

What is the best lock for a front door?

The best type of front door lock depends on a few factors such as the type of door and the building type.

  • Door Type – A Wooden door will require a different lock compared to a uPVC or Composite door, as most wooden doors have TWO locks fitted.
  • Building Type – A door lock on a flat or apartment (or a dwelling with a single exit) will have different escape requirements compared to a domestic house lock. We also recommend your door lock is independently tested (e.g., British Standard) with the correct egress requirements followed.

What brand of lock is best?

The brand of lock you choose is a personal choice, we recommend any lock that has been Independently tested, meaning a lock has met minimum security and durability needs.

What is the best lock for a wooden door?

The best lock for a wooden door is a lock that meets the requirement of BS3621, the type of lock fitted can be a nightlatch, mortice deadlock or mortice sashlock.


A non-tested nightlatch can be used for access, but it must be supported with a tested lock, so you would need to have two locks on the door. It should be noted that if a non-tested night latch is used on its own, the door is not securely locked and is in a latched state and vulnerable to attack.


Live in a flat or apartment? If the door is on a single exit dwelling (flat or apartment) then the lock should meet the requirement of BS 8621.

What is the best lock for a uPVC door?

You will usually find a multipoint lock with a Euro cylinder on most uPVC doors. However, Euro Cylinder locks are prone to lock snapping. For extra security, we recommend the lock standard of any euro cylinder on a uPVC door is either an SS312 Diamond Approved Cylinder or TS007 3 Star.

What is the best lock for a composite door?

If your composite door has been tested to PAS 24 and carries a Secure by Design certificate, then the lock has been tested to an extremely high level of attack so new locks are not needed. If the door is untested then changing the lock cylinder to a Sold Secure SS312 Diamond cylinder or TS 007 3 star cylinder will prevent locks being broken and burglars gaining entry.

What about locks for rented properties?

We are often called upon by both landlords and tenants who wish to repair, replace, and change their locks for various reasons. Often this is due to the tenant requesting the security of knowing no one else holds keys to their property, or as a condition of the tenant’s contents insurance.


The grey area is working out who is responsible for the lock work to be completed, and we therefore ask all tenants to check their tenancy agreement prior to booking in any works. Most landlords include a caveat into the tenancy agreement stating that tenants are not allowed to tamper with locks on a property without explicit landlord consent. In this case we would require proof of the landlord’s approval. Where a tenancy agreement does not hold this condition, then tenants can legally change the locks on their property under the ‘right of quiet enjoyment’ and can do this with or without their landlords’ consent. Having said this, we always recommend that you inform your landlord before making changes to the building security as it may also affect their landlord’s insurance.


The grey area is also applicable to lock repairs and emergencies. If the landlord omitted the caveat into the tenancy agreement and for example the tenant snapped their key in the lock, or the lock failed through misuse then it could also be deemed the tenant’s responsibility to rectify the issue with as little bother to the landlord as possible. Alternatively, if the landlord included the condition, then they would have to treat the scenario as an emergency and rectify the issues as soon as possible to ensure that the tenants ‘right to quiet enjoyment’ was not impacted.

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