A forced door after a break-in is stressful enough. Finding out that a lock did not meet the terms of your policy can make it far worse. So, what locks meet insurance requirements? Usually, insurers want proven security on every external door, but the exact lock required depends on your policy, door type and how the property is used.
There is no single lock called an “insurance lock”. What matters is the lock’s British Standard, how it is fitted and whether it matches the security declaration you gave your insurer. If you are unsure, check your policy wording before changing anything. A local locksmith can then assess the door itself, not just the lock fitted to it.
What locks meet insurance requirements most often?
For many UK homes, the familiar answer is a British Standard BS 3621 five-lever mortice deadlock on a timber front or back door. These locks are designed to resist common forms of forced entry and are widely recognised by insurers. You will normally see the BS 3621 marking stamped on the faceplate, visible on the edge of the door when it is open.
That does not mean every external door needs a mortice deadlock. A modern composite, uPVC or aluminium door will usually have a multipoint locking mechanism. On these doors, the key area is the euro cylinder and the handles, as well as whether the multipoint mechanism locks and engages properly.
A suitable setup may include a TS 007 three-star cylinder, or a one-star cylinder used with two-star security handles. These ratings are intended to offer better resistance to cylinder snapping, drilling and picking – methods often used against poorly protected euro cylinders.
The right solution depends on the door. Fitting a mortice lock to a uPVC door is not an alternative to repairing or securing its multipoint mechanism. Equally, fitting a high-security cylinder into a loose handle or a damaged door frame will not provide the protection it should.
The British Standards worth knowing
British Standards give you a useful starting point when comparing locks, but they are not a substitute for reading your own insurance documents.
BS 3621: mortice locks for external doors
BS 3621 is the standard most people mean when they say an insurance-approved lock. A BS 3621 lock is normally a five-lever mortice deadlock or sashlock with a key needed from both sides. It suits many timber external doors where there is no need for keyless escape from inside.
A sashlock combines a latch and deadlock in one case, while a deadlock only has the bolt. Both can meet the standard when correctly specified and fitted.
BS 8621: security with safer escape
BS 8621 is designed for doors where occupants may need to leave quickly without hunting for a key. It provides external key operation and an internal thumbturn. This can be a sensible choice for a family home, particularly where the door is part of an escape route.
However, do not assume it meets every policy condition simply because it is a British Standard. Some policies specifically request BS 3621, while others accept BS 8621 or an equivalent lock. Ask the insurer if the wording is unclear.
TS 007: protection for euro cylinders
TS 007 applies to cylinders and door furniture used on many uPVC, composite and aluminium doors. A three-star cylinder can be fitted on its own. A one-star cylinder may be paired with two-star security handles to achieve the same three-star level of protection.
Look for clear star markings or a relevant certification mark on the product. If a euro cylinder protrudes well beyond the handle, feels loose or shows signs of tampering, it is worth having it checked promptly.
PAS 24: the door set standard
PAS 24 relates to the overall security performance of a complete door set, rather than one individual lock. A newer external door may have been tested as a complete unit with its frame, hardware and glazing. This can satisfy an insurer’s security expectations, provided the door remains in good working order.
Check what your insurer actually asks for
Your policy schedule, proposal form or renewal paperwork may state specific requirements. Common wording includes a five-lever mortice deadlock to BS 3621 on final exit doors, a suitable locking system on patio doors, and key-operated locks on accessible windows.
Pay close attention to the language. A policy may say that locks must be in use whenever the property is unattended, or whenever everyone is asleep. If you declared that a particular lock was fitted when taking out the policy, replacing it with a lower-grade lock later could create a problem.
Insurers may also take a different view of a main home, a rented property, an unoccupied house and commercial premises. A landlord may need to balance insurance requirements with fire safety and tenant escape. A shop or office may need shutter locks, restricted keys or additional protection because of the stock or equipment inside.
If the requirement says “approved”, ring the insurer and ask them to confirm the exact standard they accept. Make a note of the date, the person you spoke to and what they said. It is much better to clarify this before fitting a lock than after a theft.
Why the lock alone is not the whole answer
Insurance requirements are often discussed as if the cylinder or mortice lock is the only thing that matters. In practice, a secure door relies on several parts working together: the lock, handles, keeps, hinges, frame and door panel.
A timber door with a BS 3621 lock can still be vulnerable if the frame is split around the keep or the screws are short and loose. A uPVC door can have an excellent anti-snap cylinder but fail to lock properly because the door has dropped out of alignment. If you have to lift, push or pull the handle hard to turn the key, do not leave it until the mechanism fails completely.
Patio doors deserve the same attention. Sliding doors should lock securely and have working anti-lift measures. French doors need sound locking on both leaves, not just a basic latch. Ground-floor and easily accessible windows may also need key-operated locks, depending on the policy.
Keep keys secure as well. Leaving a key in sight of a letterbox, window or glazed panel can defeat an otherwise good lock. A letterbox guard or internal key safe position may be appropriate, but make sure anyone in the property can still leave safely in an emergency.
When should you replace a lock?
Replacement is sensible after lost or stolen keys, a break-in, moving into a new property or a change of tenant. It is also worth considering if the lock is old, difficult to operate, visibly damaged or not up to the security level required by your insurer.
Not every fault needs a new lock. A sticking uPVC door may only need adjustment or a repair to the multipoint mechanism. A worn cylinder may be changed without replacing the whole door handle or mechanism. A proper inspection avoids paying for hardware that does not solve the underlying issue.
Keep invoices for lock work, particularly where a British Standard or TS 007-rated product has been fitted. They provide useful evidence of what was installed and when. Take clear photographs of the lock markings too, especially before you dispose of an old lock after a burglary.
Get the right lock fitted properly
The safest route is to start with your insurer’s wording, then have the door assessed by an experienced locksmith. They can identify whether a lock is genuinely compliant, whether the door needs repair first and whether a thumbturn option is suitable for the household.
For homeowners, landlords and businesses around Reading and the Thames Valley, Lock Solutions can inspect existing locks, explain the practical options in plain English and fit recognised security hardware without a callout charge. If a door has become difficult to lock or you are worried it does not meet your policy terms, deal with it before a failed lock leaves the property insecure.
