LOCK SECURITY • EURO CYLINDERS
Anti-snap locks explained
Lock snapping is a method of breaking a standard euro cylinder in two to release the mechanism. An anti-snap cylinder has sacrificial sections that break off and leave the working part intact and still locked. The ratings to look for are TS007 three star or Sold Secure Diamond. A replacement starts at £120.
What lock snapping actually is
A euro cylinder — the brass, figure-of-eight-shaped part your key goes into on a uPVC or composite door — is weakest at its centre, where the cam sits. A standard cylinder can be gripped and snapped there, exposing the cam and letting the mechanism be turned directly.
It became widespread because it is quick, needs no particular skill and makes very little noise. It is the main reason euro cylinder standards changed, and it is still the most common way a modern uPVC front door is forced.
The most important contributing factor is one you can check yourself in five seconds.
Check whether your cylinder projects
Look at the cylinder from outside, where it comes through the handle. If it sticks out beyond the handle plate by more than about 3mm, it is the wrong length for the door, and the part sticking out is exactly what gets gripped.
An over-length cylinder on a standard lock is the single most vulnerable arrangement in common use. Correcting it is not expensive: the fix is a cylinder of the right size, and if you are changing it anyway, changing it for an anti-snap one costs very little more.
What an anti-snap cylinder does differently
It is designed to fail in a controlled way. Sacrificial grooves let the outer section break off cleanly, leaving the central cam and the inner section in place, still engaged, still locked. What the attacker ends up holding is the part that does nothing.
Better cylinders add hardened anti-drill pins, anti-pick pins and anti-bump protection. Hardened steel inserts resist drilling at the cam. None of this makes a door impossible to get through — but it changes the job from quick and quiet to slow and noisy, which is the whole point.
The ratings that mean something
| Rating | Who issues it | What it covers |
|---|---|---|
| TS007 3 star | Door and Hardware Federation / Glass and Glazing Federation | Cylinder alone, tested against snapping, picking, drilling and bumping |
| TS007 1 star + 2 star handle | Same | A 1 star cylinder only reaches the equivalent when paired with a 2 star security handle |
| Sold Secure Diamond | Sold Secure, part of the Master Locksmiths Association | Cylinder tested against the same attacks, independently rated |
Either three star or Diamond is a reasonable specification. The trap is the one-star cylinder sold as "anti-snap": on its own it is not equivalent, and it only reaches three-star performance when fitted with a two-star handle, which is often not what gets installed.
"Anti-snap" is not itself a certification. The star rating or the Diamond mark is.
Is it worth it?
For a uPVC or composite front door with a standard cylinder, particularly one that projects, it is one of the better pieces of security spending available — a modest sum against the most commonly used method of entry.
It is less compelling where the door is not the weak point. A back door hidden from the street with a glazed panel next to the handle, or an unsecured side gate giving access to the rear, will be used first. Upgrading a front cylinder while the side gate stands open changes very little, and we would rather say so than sell you a cylinder.
What it costs
A euro cylinder replacement is listed from £120, supplied with new keys, with call-out and labour charged separately at the published rates. Cylinders can be supplied keyed alike where a property has several doors, so one key covers them all.
If you are already having a lock changed after losing keys or moving house, specifying anti-snap at that point costs very little extra, because the labour is the same either way.
Common questions
What is lock snapping?
Breaking a euro cylinder at its weakest point, at the centre, to expose the cam and turn the mechanism directly. It is quick, quiet and requires no skill, which is why it is the most common way a uPVC front door is forced.
How do I know what size euro cylinder I need?
Measure from the centre of the fixing screw hole to each end separately, with the cylinder in the door. The two halves are often different lengths, and that is normal. Our guide to measuring a euro cylinder covers it step by step.
Is a one-star anti-snap cylinder good enough?
Not on its own. A TS007 one-star cylinder only reaches equivalent protection when paired with a two-star security handle. If you are buying one component rather than both, a three-star cylinder or a Sold Secure Diamond one is the simpler specification.
Will an anti-snap cylinder stop a break-in?
No lock stops a determined attempt. It removes the quickest and quietest method, which means more time and more noise. That is a real improvement, and it is also the honest limit of what a cylinder can do.
Does my insurer require anti-snap locks?
Rarely in so many words, though some policies now mention cylinder standards. Policy wording more often addresses mortice locks on timber doors. Read your own document, and do not accept a claim about your cover from anyone who has not read it.
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