Locksmith Advice & Home Security Guides

Lock snapping is the most common way intruders beat a uPVC or composite door, and most people have never heard of it. The euro cylinder — the barrel your key goes into — has a deliberate weak point in the middle. With basic tools and a few seconds it can be snapped in two and the lock turned, often leaving little obvious damage from the street. The standard builder’s-spec cylinders fitted to most doors are vulnerable to it.

The good news is that it is one of the cheapest security problems to fix. A BSI Kitemark anti-snap cylinder — 1 Star, or 3 Star on its own — is engineered to break in a controlled way that defeats the attack and keeps the door locked. You can often spot a vulnerable cylinder because it protrudes past the handle and carries no anti-snap markings. If yours looks like that, it is worth changing before you ever need to.

Most uPVC doors are more vulnerable than they look, but a few targeted upgrades make a real difference. The single biggest one is the cylinder: replacing a standard euro cylinder with a BSI Kitemark anti-snap (1 Star or 3 Star) shuts down lock snapping, the most common attack.

Beyond that, simple habits matter — lift the handle fully to throw the hooks and bolts, turn the key to lock it, and take the key out, because a door left on the latch is doing nothing. Check the multipoint mechanism is engaging cleanly; a door you have to lift or lean on to lock is wearing out and worth servicing. Hinge bolts and a well-fitted restrictor add resistance, and a quick security check will flag anything weak. None of it is expensive, and together it turns a soft target into a hard one.