The short answer
An anti-snap lock is a Euro cylinder designed to resist lock snapping, where a burglar breaks the cylinder in half to open the door. The two main ratings to look for are TS007 3-star and Sold Secure Diamond. If your uPVC or composite door has an older standard cylinder, upgrading is one of the quickest and best-value security improvements you can make.
What is lock snapping?
Most uPVC and composite doors use a Euro cylinder, the part you put your key into. Older cylinders have a weak point in the middle. With force, a burglar can snap the cylinder at that point and open the lock in seconds. Anti-snap cylinders have a sacrificial section that breaks away while the part that holds the lock stays in place.
What does TS007 3-star mean?
TS007 is a Kitemark scheme for cylinders and door handles. The stars add together:
| Set-up | Total rating |
|---|---|
| 3-star cylinder on its own | 3 stars |
| 1-star cylinder plus 2-star security handles | 3 stars |
| 1-star cylinder with standard handles | 1 star only |
For most homes, a 3-star cylinder is the simplest route because it gives full protection whatever handles you have.
What is Sold Secure Diamond?
Sold Secure Diamond (SS312) is a separate test that many locksmiths see as tougher than TS007 3-star. Many good anti-snap cylinders carry both marks.
How to check your cylinder
- Open the door and look at the face of the cylinder, around the keyhole.
- Look for the Kitemark with stars, or the Sold Secure Diamond logo.
- Check how far the cylinder sticks out from the handle. More than about 3mm makes snapping easier.
- If there is no marking, treat it as a standard cylinder.
How much does an anti-snap upgrade cost?
Checkatrade's May 2026 cost guide puts an anti-snap uPVC lock at about £150 fitted. Changing several doors on one visit lowers the cost per door, and we can key cylinders alike. We give you a written price for your doors first.
Related service: anti-snap lock upgrades in London.
A few common questions
What is an anti-snap lock?expand_more
An anti-snap lock is a Euro cylinder built to resist lock snapping, where a burglar breaks the cylinder to open a uPVC or composite door. It has a sacrificial section that breaks away while the locking part stays in place. Look for TS007 3-star or Sold Secure Diamond markings on the cylinder face.
What does TS007 3-star mean?expand_more
TS007 is a Kitemark scheme for door cylinders and handles. Stars add up: a 3-star cylinder on its own gives a 3-star rating, or a 1-star cylinder plus 2-star security handles also gives 3 stars. A 3-star cylinder is the simplest choice because it protects the door whatever handles are fitted.
Is Sold Secure Diamond better than TS007 3-star?expand_more
Sold Secure Diamond is a separate test that many consider tougher than TS007 3-star, especially against snapping and other attacks. Both are strong ratings. Many quality cylinders carry both marks, which gives you extra confidence that the lock has been independently tested.
How do I know if my lock is anti-snap?expand_more
Look at the face of the cylinder around the keyhole for the Kitemark with stars or the Sold Secure Diamond logo. If there is no marking, assume it is a standard cylinder. Also check it does not stick out more than about 3mm from the handle, as that makes snapping easier.
How much does it cost to fit an anti-snap lock?expand_more
Checkatrade's May 2026 cost guide puts an anti-snap uPVC lock at about £150 fitted. Doing several doors on one visit lowers the cost per door, and we can key the cylinders alike so one key opens all of them. Ask for a written price before work begins.