Look at the cylinder, the part your key goes into. A BSI Kitemark with three stars, or Sold Secure Diamond (SS312) approval, means it has been tested against snapping. One star alone does not count unless the handle carries a 2 star mark, and with no mark or paperwork, treat it as standard.
Start with the outside face of the cylinder, around the keyhole. The Master Locksmiths Association says the Kitemark can appear anywhere on the lock but is usually on the front or the side of the cylinder. A mark on the side only shows when the cylinder is out of the door, so a blank face does not always mean there is no mark.
Count the stars beside the Kitemark. Under TS007, three stars on a cylinder means it was tested for resistance to snapping. One star means basic approval with no snap test, so a 1 star cylinder only reaches the 3 star level when the handle or cylinder guard carries its own 2 star Kitemark. Check the handle as well as the lock.
Sold Secure Diamond cylinders are listed on the Sold Secure website, so if you know the make and model of your cylinder, you can check it there. Paperwork helps too. The receipt, or the documents that came with the door, may name the cylinder and its standard. If a locksmith fitted it, ask them what it was tested to.
Then check how far the cylinder sticks out. The association advises that a euro cylinder should not stand more than 3mm proud of the handle and ideally sits flush, because a more exposed cylinder is more prone to snapping. If you find no mark and no paperwork, send your job through the form or the chat, and parts are named and priced before we set off.
Useful next steps
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