UK Lock Types Explained

Yale rim latches sit on the inside face of the door, not in the door edge. The latch is the spring-loaded bolt that catches when you close the door. Outside, you see a small round cylinder with a keyway. Inside, you see a chunky case with a thumbturn. They're quick to use because they self-lock when the door closes, but on their own they're not insurance-grade — they need to be paired with a mortice deadlock for compliance.

Common UK brand names: Yale, ERA, Union, Squire. Sizes are mostly standardised (60mm or 70mm backset). Repair is usually a £45-65 service for a worn cylinder; replacement is £85-120 fitted with a new cylinder and case.

Mortice deadlocks sit inside the body of the door — you see only the brass faceplate on the door edge and a keyway on each side. They use a deadbolt that throws into the door frame when you turn the key. The British Standard BS3621 mortice deadlock is the security workhorse of UK wooden doors. Look for the Kitemark stamped on the brass faceplate to confirm BS3621 compliance.

Repair (worn lever spring, jammed mechanism): £65-85. Replacement with a new BS3621-compliant lock: £150-180 fitted. The job takes 1-2 hours per door because the existing mortice may need to be enlarged to fit the new lock body.

Euro cylinders are the long horizontal lock that runs through UPVC and composite doors. The keyway is in the centre, with a cam at the back that drives the multipoint locking mechanism. Standard euro cylinders are vulnerable to lock snapping — a 10-second attack with mole grips that breaks the cylinder along its centre line and exposes the cam.

TS007 3-star anti-snap cylinders defeat this attack. Look for the small Kitemark with star count on the front of the cylinder face. 3-star is the modern minimum we recommend on UPVC and composite doors. Replacement cost: £85-180 fitted depending on cylinder grade and brand.

When you lift the handle on a UPVC or composite door, you're driving a multipoint locking mechanism — a system of hooks, deadbolts, and rollers that engage at 3-5 points along the door edge simultaneously. The mechanism is driven by the cam on the euro cylinder. Common UK manufacturers: Yale, ERA, GU, Maco, Winkhaus, Mila, Avocet, Fullex.

When the central gearbox in the multipoint mechanism fails, the door won't lock at all even though the key turns. Replacement is £125-150 fitted, takes 30-60 minutes, and saves the £600-1,200 a new UPVC door installation would cost.

UK smart locks (Yale Connect, Nuki, August, SwitchBot) are mostly retrofit devices that fit on the inside of the door over the existing thumbturn and physically rotate the cylinder when commanded by app, fob, keypad, or voice. The outside of the door looks unchanged; the original key still works. Battery-powered, with the original key as fallback.

Insurance acceptance is increasingly standard provided the underlying mechanical lock meets BS3621 / TS007 3-star. Cost: £180-400 fitted depending on brand. Avoid sub-£80 unbranded models — they often have weak encryption and known exploits.

Sash window locks: small key-operated bolts that lock the bottom and top sashes of a sliding window. Insurance often requires functional locks on accessible windows. £15-30 fitted per window.

Patio sliding door locks: usually a hook-bolt with a key cylinder, plus a foot-bolt at the bottom. Replacement: £85-150 depending on the door manufacturer.

Key safes: police-approved Sold Secure 'Gold' rated key safes are the only ones insurers accept for outside-the-house key storage. £80-120 fitted including a Sold Secure-rated unit and proper anchoring.

Wooden front door (Victorian or Edwardian terrace): Yale rim latch on top, BS3621 mortice deadlock below. Modern wooden door (post-war semi): same combination. UPVC front door (any age): TS007 3-star euro cylinder driving a multipoint mechanism, typically with a separate hook-bolt latch in the central handle. Composite door (modern, looks like wood but is GRP): TS007 3-star euro cylinder + multipoint, usually with a single multi-bolt mechanism. Patio sliding door: usually a hook-bolt with key cylinder, plus a foot-bolt at the bottom.