A front door can look secure and still fall short of what your insurer expects. This guide to insurance approved locks explains what the term really means, which standards matter, and how to avoid finding out after a burglary that the lock on your door was not suitable for your policy.
The right answer depends on your door, how you use the property and the wording of your insurance. A Victorian timber door, a modern composite door and a commercial rear entrance do not all need the same lock. What matters is fitting a properly tested product correctly, then keeping evidence of the work.
What does insurance approved actually mean?
“Insurance approved” is widely used, but it is not a single approval badge issued by every insurer. Usually, it means a lock meets a recognised British Standard or security rating that an insurer may require or accept as part of its policy conditions.
For many domestic timber doors, the best-known standard is BS 3621. A lock carrying this standard has been tested for resistance to common forced-entry methods. You will often see it on high-quality mortice deadlocks and certain rim locks. Look for the British Standard kite mark and the BS number on the lock itself, not simply on packaging or in an online description.
Your insurer may specify a standard, a type of lock, or a general requirement such as “five-lever mortice deadlocks on external doors”. The detail matters. Not every five-lever mortice lock meets BS 3621, and an older lock may not meet a current policy requirement even if it has served the door for years.
Before arranging an upgrade, read the security section of your policy schedule. If the wording is unclear, ask the insurer to confirm what it requires for each external door and accessible window. This is particularly worthwhile after moving home, changing insurer, converting a property into a rental, or carrying out an extension.
A guide to insurance approved locks by door type
Timber front and back doors
A solid timber door is commonly fitted with a mortice deadlock, a rim nightlatch, or both. Where an insurer asks for a deadlock, a BS 3621 five-lever mortice deadlock is often the appropriate choice. When locked, it should throw a substantial bolt into a secure keep in the frame.
A nightlatch provides useful day-to-day convenience, but a basic model should not automatically be treated as an insurance-approved security lock. High-security rim locks are available, including models tested to BS 3621, and may be suitable where the door design calls for one. The condition of the frame, keeps, hinges and door panels is just as relevant as the lock body.
If the door has decorative glass close to the lock, speak to a locksmith about safe egress and the most appropriate lock arrangement. Security must not make it harder for occupants to leave quickly in an emergency.
uPVC and composite doors
Most uPVC and composite doors use a multipoint locking mechanism operated by lifting the handle and turning a euro cylinder. The mechanism may lock at several points around the door, but the cylinder is often the part most exposed to attack.
For this type of door, a TS 007 3-star euro cylinder is a common high-security upgrade. These cylinders are designed to resist methods such as snapping, drilling and picking to a tested standard. An alternative arrangement can sometimes combine a 1-star cylinder with 2-star security furniture, provided the components are compatible and correctly fitted.
A 3-star cylinder is not a cure for a poorly aligned door. If the handle must be forced upwards, the key sticks, or the door has dropped on its hinges, the multipoint mechanism can wear or fail. Have the door adjusted and the locking points checked at the same time as the cylinder upgrade.
Patio, French and sliding doors
These doors need individual assessment. Some use multipoint locks and euro cylinders, while others have dedicated handles, hook bolts or shoot bolts. Their security can also depend on anti-lift devices, glazing, track condition and the strength of the frame.
Do not assume a replacement cylinder alone will resolve a weak patio door. The lock must engage fully and the door must close tightly into its keeps. A professional inspection can identify whether the issue is the cylinder, the mechanism, the alignment or the surrounding door furniture.
Flats, shared entrances and commercial premises
A flat entrance door may have fire-door requirements as well as security requirements. Changing the lock specification without considering fire safety, the communal entrance system or the lease can create problems. In these cases, check with the managing agent or landlord before work begins.
For shops, offices and managed properties, insurers may require particular standards for rear doors, stock rooms, shutters or restricted areas. The level of cover, the value of stock and whether the premises are left vacant overnight can all affect the required security. A lock upgrade should be part of a wider review of the door, frame and access arrangements rather than a one-size-fits-all purchase.
The standards you are most likely to see
BS 3621 is generally associated with thief-resistant locks that require a key to operate from the inside. That can suit some external doors, but it is not always ideal where people need to exit without searching for a key.
BS 8621 covers locks designed to allow keyless escape from the inside, such as a thumbturn operation. It can be a sensible option for occupied homes, especially where a key-operated lock could delay an escape. The trade-off is that a thumbturn near unprotected glazing needs careful consideration.
BS 10621 also relates to thief-resistant locks with keyless operation from inside and outside in certain applications. The right standard is not simply the highest number. It must suit the door, occupants and insurance conditions.
TS 007 is a separate rating commonly seen on cylinders and door furniture. A 3-star cylinder offers a high level of tested protection on euro-cylinder doors. Check the marking on the cylinder, and make sure it is the correct length. A cylinder that protrudes too far beyond the handle can create an avoidable security weakness.
Correct fitting is part of the security standard
A quality lock fitted badly can be less secure than a modest lock installed properly. The mortice lock needs to sit accurately in the door, the keep needs secure fixings into sound timber or a reinforced frame, and the bolt must engage fully when locked.
On a uPVC or composite door, the cylinder should sit flush or only very slightly proud of the security handle. The handles must be firmly fixed, and the multipoint lock should engage without excessive pressure. If a key only turns when you pull the door towards you, that is a sign the door or keeps may need adjustment.
Keep paperwork for any upgrade. An invoice that records the lock type, standard and work completed can be useful if you need to discuss security with your insurer later. It also gives landlords and property managers a clear maintenance record.
Common mistakes that can affect a claim
The most serious mistake is failing to comply with a clear policy condition. If your insurer requires specified locks to be fitted and used whenever the property is empty or overnight, leaving them unsecured could affect a claim following a break-in.
Another frequent issue is assuming that a new-looking lock is a high-security lock. A replacement cylinder may operate smoothly but offer little resistance to modern attack methods. Likewise, fitting a high-security cylinder into a door with loose handles, a damaged frame or failed locking points leaves other weaknesses unaddressed.
Landlords should also consider who has access after a tenancy ends. Changing external locks between occupancies is sensible security practice, particularly where keys may have been copied or not returned. For business owners, access control should be reviewed when staff with keyholder responsibilities leave.
When to call a locksmith
Call for professional advice if you have just moved in, your insurer has requested security improvements, your door has been damaged during an attempted break-in, or the lock is stiff, loose or unreliable. Acting before it fails can prevent a lockout and reduce the risk of further damage to the door mechanism.
DGM Locksmiths can assess timber, uPVC and composite door security across Birmingham and the West Midlands, explain the suitable options clearly and fit high-security locks with care. For urgent faults or post-burglary lock repairs, a prompt inspection helps restore security without unnecessary disruption.
The most useful next step is simple: check what your policy says, inspect whether every external door locks properly, and address any uncertainty before you need to rely on the protection your insurance is meant to provide.