A lock can look substantial and still fall short of the condition in your insurance policy. The question, what locks meet insurance standards, has no single answer because insurers assess the type of door, the property, its location and the cover you hold. However, there are recognised British Standards that insurers commonly ask for, and checking them before a burglary or claim gives you far greater peace of mind.
For most homes, the crucial point is not simply having a lock fitted. It is having the right type of tested lock, fitted properly to a sound door and frame, while meeting the precise wording of your policy.
Insurance-approved locks: what insurers usually mean
Insurance companies do not generally manufacture or approve locks themselves. Instead, policy documents often specify a recognised standard, such as BS 3621, or describe the lock arrangement required on particular doors. You may see wording such as “five-lever mortice deadlock conforming to British Standard BS 3621” or a requirement for an approved multipoint locking system.
A lock meeting the relevant standard has been independently tested for resistance to common forced-entry methods. That matters, but it does not mean every insurer will automatically accept every lock carrying a standard. If your policy names a particular product type or standard, that wording takes priority.
The most reliable approach is to read the security section of your buildings and contents policy, particularly any endorsements or special conditions. If it is unclear, ask the insurer to confirm its requirements in writing before changing your locks.
What locks meet insurance standards for wooden doors?
For traditional timber front and back doors, the lock most commonly associated with insurance requirements is a BS 3621 five-lever mortice deadlock. These locks are fitted into the edge of the door and have a bolt that throws into the frame when locked with a key.
A BS 3621 lock is designed to provide a higher level of attack resistance than a basic mortice lock. It is often identified by the British Standard number and a BSI Kitemark on the faceplate or packaging. A standard five-lever lock is not necessarily a BS 3621 lock, so the marking is important.
A mortice sashlock can also meet BS 3621 where it carries that exact rating. The difference is that a sashlock includes a latch operated by a handle, while a deadlock has only the locking bolt. The correct choice depends on how the door is used and whether a separate latch or nightlatch is already fitted.
Many older doors have a Yale-style nightlatch as their main lock. A basic nightlatch alone may not meet an insurer’s requirement for a final exit door. Some insurers accept a suitable high-security nightlatch, while others specifically require a BS 3621 mortice deadlock in addition to it. This is one area where assumptions can be costly.
Locks for uPVC, composite and aluminium doors
Modern uPVC, composite and aluminium doors usually use a multipoint locking mechanism. When you lift the handle and turn the key, several hooks, rollers, bolts or mushroom cams engage along the door edge. The cylinder in the handle controls the mechanism.
For these doors, insurers may refer to a multipoint lock, but the security of the cylinder is equally significant. Lock snapping has been a common method of attack on poorly protected euro cylinders. A cylinder that is vulnerable to snapping can allow an intruder to operate the locking mechanism even though the rest of the door appears secure.
A sensible benchmark is a TS 007 three-star cylinder or an SS312 Diamond cylinder. Both indicate tested resistance to lock snapping and other forms of cylinder attack. Another recognised arrangement is a one-star cylinder paired with two-star security handles, giving a combined three-star TS 007 rating.
The ratings must be considered as a complete setup. Replacing only the cylinder may improve security, but it does not automatically prove that the door, handles, keeps and frame satisfy a particular insurance condition. A poorly aligned multipoint door can also fail to lock correctly, leaving hooks or bolts only partly engaged.
When BS 8621 or BS 10621 may be appropriate
Some doors need a lock that allows occupants to leave quickly without a key. This is especially relevant where a key-operated lock on the inside could create a fire-escape concern. British Standards including BS 8621 and BS 10621 cover thief-resistant locks with keyless egress arrangements.
These locks can be appropriate for particular homes, flats and shared buildings, but they are not automatic replacements for BS 3621. If your insurance schedule expressly calls for BS 3621, fitting a thumbturn lock to another standard without checking first could create a problem. Fire safety, emergency escape and insurance conditions should be considered together rather than in isolation.
This is also why a lock should never be selected on security alone. The best arrangement is one that protects the property without making it harder for people to get out safely in an emergency.
Other doors that can affect insurance cover
Insurers may apply different requirements to rear doors, French doors, patio doors, garage doors, outbuildings and side gates. These are common entry points, particularly where they are less visible from the street.
For patio and French doors, the locking system must secure the door properly into its frame and any accessible cylinders should have appropriate anti-snap protection. A simple key lock added to a weak handle, loose keep or damaged frame will not provide the protection expected from the whole door assembly.
Garages and sheds may have separate conditions, particularly when they contain bicycles, tools or garden equipment. A quality closed-shackle padlock and suitable hasp can be part of the solution, but the structure being secured matters just as much. A strong padlock on a thin, poorly fixed hasp offers limited resistance.
For flats, landlords and managing agents may control communal entrance doors and fire doors. Do not alter these without permission or without ensuring the replacement is appropriate for the door’s fire rating and access requirements.
How to check whether your existing locks are acceptable
Start with your insurance documents. Look for terms such as “minimum security”, “door security”, “approved locks” and “special conditions”. Note whether the requirements apply when the property is occupied, unoccupied or left for a specified number of days.
Next, inspect the lock markings where possible. A BS 3621 mortice lock commonly shows its standard on the faceplate at the edge of the door. TS 007 and SS312 ratings are usually found on the cylinder, packaging or product documentation. If no clear markings are visible, do not guess based on the number of keys, the lock’s age or its appearance.
It is also worth checking how the door closes. The lock may be correctly rated but unable to perform properly if the door has dropped, the frame has moved or the strike plate is loose. On a multipoint door, lift the handle fully and make sure the key turns smoothly without forcing it.
A professional assessment is particularly worthwhile if you have just moved home, suffered an attempted break-in, lost keys, inherited older locks or are changing insurers. It can identify vulnerabilities that are easy to miss, including weak cylinders, worn mechanisms and incorrect previous fitting.
Commercial premises need a wider security plan
For shops, offices, workshops and managed properties, insurers may specify security levels for external doors, shutters, safes, alarm systems and key control. The required standard may depend on stock value, cash handling, business hours and whether the premises are vacant overnight.
A high-security lock is only one part of the picture. A rear service door with a poorly fitted frame, a shared key with no record of who holds it, or an unsecured fire exit can undermine an otherwise well-protected site. Commercial clients often benefit from a practical survey that considers access control, master key arrangements and the condition of every external opening.
Fitting matters as much as the lock
A correctly rated lock fitted badly can be easier to defeat than a modest lock fitted well. Mortice locks need adequate timber around the case and secure fixings into a sound frame. Cylinders should be the correct length, sit neatly with the handle and not project excessively beyond it. Multipoint doors need alignment so every locking point engages as intended.
KBO Lock & Safe can assess existing door security, explain the relevant standards in plain English and fit suitable locks for homes and businesses across the local area. The aim is not to sell the most expensive lock, but to provide a properly fitted solution that matches the door, the way you use it and your insurer’s conditions.
Before renewing a policy or replacing a lock after a problem, take a few minutes to verify what your insurer actually asks for. That small check can help protect your property, avoid uncertainty during a claim and ensure the people behind the door can feel properly secure.
