There is no single lock specification that every UK home insurer requires. The requirement that matters is the wording on your own policy schedule, statement of fact, endorsements and security questions. Some policies accept standard door locking arrangements, while others apply a specific “minimum security” condition for theft cover.
Terms commonly encountered include BS 3621 locks on suitable timber doors, multipoint locking with a stated number of points, key-operated window locks, specific patio or French-door arrangements and requirements to actually use the declared security when the property is unattended.
This guide explains what those terms mean, how to check your documents before changing locks, and what information to give a locksmith so a security upgrade matches the policy rather than relying on assumptions.
Insurance Lock Requirements: The Short Answer
- Read your own policy documents first. The schedule and endorsements override generic internet advice.
- Check what you declared. Insurers may ask what locks are fitted to doors and windows when quoting.
- Do not assume “five lever” automatically means compliant. Look for the exact standard or security condition named in the policy.
- Multipoint doors are assessed differently from timber mortice-lock doors. Many policies describe them separately.
- Use the security you declared. A fitted deadlock or window lock is not useful if policy wording requires it to be engaged and it is left unused.
- Keep evidence after upgrades. Invoice, product markings, keys and photographs can help you record what was fitted.
Start with the Policy, Not the Lock
Home-insurance questions often ask about locks because security can affect underwriting, terms or price. The safest order is: policy schedule, endorsements, statement of fact/proposal information, then the main policy booklet. Search for phrases such as “minimum standards of security”, “theft”, “unoccupied”, “doors and windows” and “security protections”.
| Document | What to look for | Why it matters |
|---|---|---|
| Policy schedule | Endorsement codes, special conditions, insured address | Shows terms applying specifically to your policy |
| Statement of fact | Answers about door/window locks, alarms, occupancy | Confirms what the insurer believes is installed |
| Policy booklet | Definitions, theft exclusions, security conditions | Explains how cover operates |
| Renewal documents | Changed terms or new endorsements | Requirements can change at renewal |
| Written insurer confirmation | Acceptance of an unusual door/lock arrangement | Useful where standard wording does not fit the property |
What Does BS 3621 Mean?
BS 3621 is a British Standard for thief-resistant mechanically operated single-point lock assemblies that are key-operated from both sides. In practice, homeowners most often encounter the marking on suitable mortice or rim lock assemblies used on timber doors.
Do not apply BS 3621 blindly to every door material. uPVC, aluminium and many composite doors commonly use multipoint systems and are often described separately in insurance requirements.
What Does BS 8621 Mean?
BS 8621 covers thief-resistant single-point lock assemblies that can be unlocked from inside without a key, allowing keyless egress. This distinction can matter where escape requirements make an internally key-operated lock unsuitable.
The correct choice depends on the door, building use, fire strategy and insurer wording. A locksmith can identify the existing hardware, but the insurer should confirm whether a proposed arrangement satisfies a policy condition where there is doubt.
What About Multipoint Locks on uPVC and Composite Doors?
Multipoint systems use several locking points along the door edge, such as hooks, rollers, mushrooms or bolts, driven by a central gearbox. Policy endorsements may specify a minimum number of locking points rather than a BS 3621 single-point lock.
A multipoint door is only as reliable as its full system. Door drop or poor keep alignment can prevent points engaging even when the cylinder turns. If a security upgrade is planned, the cylinder, handles, gearbox, strip, keeps and door alignment should be considered together.
Common Door Types and the Questions to Ask
| Door/opening | Common insurance/security wording | What to verify |
|---|---|---|
| Timber final-exit door | BS-standard mortice/rim lock, sometimes additional latch | Exact standard marking and correct installation |
| uPVC/composite door | Multipoint locking, sometimes minimum number of points | Full engagement, cylinder security and door alignment |
| Sliding patio door | Hook lock, multipoint system or additional key-operated devices | Anti-lift protection and exact policy condition |
| French/double doors | Lock on active leaf plus secure bolts/locking on first-closing leaf | Which leaf closes first and how both leaves are secured |
| Accessible windows | Key-operated locks may be required by some endorsements | Which windows count as accessible under the policy |
| Garage/internal access door | Varies significantly by insurer and layout | Whether it is treated as an external access route |
Five-Lever Mortice Deadlock: Is That Enough?
“Five lever” describes part of a lock’s mechanism; it does not by itself prove that a lock meets the exact British Standard named by an insurer. If a policy asks for BS 3621, look for the appropriate kitemark/standard marking on the lock or faceplate and confirm the product and installation are suitable.
An old five-lever lock with no clear certification should not be presented to an insurer as compliant unless its status can be verified.
Do Insurers Require Window Locks?
Some minimum-security endorsements require key-operated locks on accessible windows or openings. The definition of “accessible” may include ground-floor windows and openings reachable from roofs, porches, extensions, balconies or other structures.
Do not assume every window must be retrofitted without reading the policy. Escape windows, heritage properties and unusual openings may need a different discussion with the insurer and, where relevant, fire-safety advice.
Patio and French Doors Need Their Own Check
Sliding, French and double doors are often described separately because their locking arrangements differ from a single hinged entrance door. Insurers may ask for hook locks, multipoint engagement, anti-lift measures or additional key-operated bolts depending on the policy.
Do Not Upgrade One Part in Isolation
A high-security cylinder cannot compensate for loose keeps, weak handles, poor door alignment or a multipoint strip that does not fully engage. Insurance compliance and physical security both depend on the installed system working as intended.
What If the Policy Says “Minimum Standards of Security”?
Treat that as a condition requiring careful reading. Some policies make theft cover subject to specified locks being fitted and used. Others only apply the endorsement if it is shown on the schedule. The exact wording determines the effect.
If your doors cannot meet the wording because of age, design, listed-building restrictions or fire-safety requirements, ask the insurer to confirm an acceptable alternative in writing before work is carried out.
What If You Told the Insurer the Wrong Lock Type?
Correct the information rather than waiting for a claim. Take photographs, identify the lock type and contact the insurer or broker. The appropriate outcome might be a policy correction, an upgrade request or confirmation that the existing arrangement is acceptable.
Do not guess at terminology on a quote form. If necessary, use local locksmith advice in Northampton to identify what is physically fitted, then give that information to the insurer.
Changing Locks After Moving Home
When moving into a property, previous key control may be unknown. Replacing or rekeying appropriate locks can restore control over who has access. Use the opportunity to record the door type, cylinder dimensions, lock markings and any policy security requirements.
For a broader assessment, KMI’s locksmith and security services can review door hardware and discuss suitable upgrade options without assuming every door needs the same product.
Lost or Stolen Keys
Many home policies provide some form of lock/key replacement cover, but limits and triggers vary. If keys are stolen with information that identifies the property, security is more urgent than if a single unlabelled spare is misplaced.
Contact the insurer if you intend to claim before authorising non-emergency work where policy terms require approval. In an immediate security risk, prioritise making the property secure and keep invoices and evidence.
Evidence Worth Keeping After a Lock Upgrade
- dated locksmith invoice describing the products fitted;
- photographs of the door and lock after installation;
- close-up of visible British Standard/security markings where present;
- manufacturer paperwork and guarantee;
- number of supplied keys and any key-control card;
- notes of insurer or broker confirmation;
- updated statement of fact at renewal if required; and
- records of any alarm or additional security declared alongside the locks.
Insurance Requirement vs Security Upgrade
| Situation | Priority | Best next action |
|---|---|---|
| Policy explicitly names a lock standard | Compliance with exact wording | Verify marking/installation and ask insurer if uncertain |
| No special security endorsement | Appropriate risk-based security | Improve weak points without inventing policy requirements |
| Multipoint door is stiff | Restore full engagement first | Correct alignment/mechanism before cylinder-only upgrade |
| Keys lost/stolen | Restore key control | Check policy cover and change/rekey as appropriate |
| Unusual/heritage/fire door | Balance security, safety and building constraints | Get insurer confirmation and competent specification |
Lock and Security Upgrades in Northampton
KMI Locksmiths can identify existing locks, replace cylinders and lock cases, repair multipoint systems and discuss security upgrades for homes in Northampton and surrounding areas. A locksmith can confirm what is fitted; your insurer confirms what its policy requires.
Learn more about the local KMI Locksmiths team before booking an assessment.
Final Insurance Lock Checklist
- find the latest policy schedule and endorsements;
- check the lock/security answers on the statement of fact;
- identify each final-exit, patio, French and accessible window arrangement;
- record visible standards and security markings;
- confirm multipoint locks fully engage without force;
- ask the insurer about any mismatch before a claim happens;
- obtain written acceptance for unusual alternatives;
- keep invoices and product details after upgrades;
- update the insurer at renewal where required; and
- remember that a stronger lock does not correct a weak door, frame or poor alignment.
The safest answer to “what locks does my insurer require?” is the exact requirement in your own current policy. Use standards and locksmith advice to understand and meet that wording, not to replace it with a generic rule.