Lock Upgrade Service — BS3621 & High-Security Locks

Lock Upgrade Service

A lock upgrade is one of the most cost-effective home security improvements you can make. The difference in forced-entry resistance between a standard lock and a British Standard-rated or Secured by Design lock is significant — and the price difference is modest.

Why Upgrade?

Insurance compliance is the most common driver. Standard home insurance policies include lock conditions, and if you make a burglary claim with non-compliant locks, the insurer can reduce or refuse the payout. A BS3621 lock fitted by a professional locksmith is evidence of compliance.

Security improvement is the other driver. Most residential burglaries in the UK are opportunistic. A burglar targeting a street will try the easiest doors first. Visible high-quality locks are a deterrent. Locks that resist picking, drilling, and snapping significantly raise the effort required for forced entry.

Security Ratings Explained

BS3621 — British Standard for thief-resistant locks. Covers mortice deadlocks, sash locks, and rim deadlocks. The minimum standard required by most home insurers. Look for the kitemark on the lock body.

Sold Secure — An independent testing and certification scheme with Bronze, Silver, and Gold/Diamond grades. Diamond is the highest and covers high-security cylinders and padlocks.

Secured by Design — A police-backed specification used in new build developments. Locks and cylinders meeting this standard are tested for all common attack methods.

Anti-snap cylinders — For UPVC and composite doors, an anti-snap euro cylinder is the most important single security upgrade. It neutralises the most common forced-entry method used on modern UK homes.

What We Upgrade

Front door — typically a BS3621 five-lever mortice deadlock combined with an anti-snap euro cylinder if the door has a multipoint lock.

Back and side doors — often overlooked but frequently targeted. BS3621 mortice or sash lock as a minimum.

UPVC and composite doors — cylinder upgrade to anti-snap, anti-pick, anti-drill. We can also assess whether the multipoint mechanism is functioning correctly.

Patio doors — specialist patio door locks, door pins, and security bars.

Windows — key-operated window locks for ground-floor and accessible windows.

Smart Locks

We can also advise on and fit smart lock systems that provide keyless entry, remote access control, and entry logs. Smart locks vary widely in security quality; we only recommend models that also carry British Standard or equivalent certification.