What does it mean when a lock is up to BS3621 standards?

In order to be covered by their insurance, insurance companies will normally request that your locks are compliant with the British Standards (BS3621). These locks need to be five point lever design, and will have shown in testing that they are anti-theft and resistant to attacks including drilling. They must also have an anti-pick mechanism. A useful way to identify a British Standard lock is to look for an engraved kite mark on the cylinder.