Most UPVC doors use ‘Euro-profile’ cylinders which have an inherent weakness at the centre point. If the end of the cylinder is exposed on the outer side of the door, simple tools such as mole grips can be used to grip and twist the cylinder while in situ within the locking mechanism. This can cause it to snap and it can then be removed which means the door can be opened without a key, regardless of the number of hook bolts or locking points on the door. Sometimes, the handle back plate is broken to expose the end of the cylinder to facilitate the crime. This is becoming more common but it can be prevented very easily by installing an ‘anti-snap’ cylinder.
The standard Euro Cylinder is on the left and the weak part is directly under the cam in the centre. The anti-snap cylinder on the right has grooves just in from either end of the cylinder. This means the cylinder will snap at a point where the locking mechanism cannot be attacked.
The new lock should have a technical specification TS007 and have a British kitemark.