A secure front door needs a well-made door and frame, a good lock and a cylinder that resists snapping. In the UK, look for a doorset tested to PAS 24, a euro cylinder rated TS 007 3-star or Sold Secure SS312 Diamond, and ideally products accredited by Secured by Design, the police security initiative.
Security labels on doors and locks can look like alphabet soup. Stars, kitemarks, "anti-snap" claims and police logos all appear on the packaging, and not all of them mean the same thing. This guide explains the main UK standards in plain English, using guidance from Secured by Design, Sold Secure, BSI and the Master Locksmiths Association (MLA), so you know what to ask for when you buy a new door or upgrade the lock on your current one.
What makes a front door secure?
A door is only as strong as its weakest part. Secured by Design points out that a lock's test result does not cover the door, the frame or the other hardware, all of which affect how well the lock performs in real life. In practice, security depends on:
- The doorset: the door leaf, frame, hinges, glazing and locking hardware working together.
- The lock: on most uPVC and composite doors this is a multipoint lock that bolts into the frame in several places.
- The cylinder: the keyed barrel that operates the lock. On many modern doors this is a euro cylinder, and it is often the main target.
- The handle or escutcheon: security door furniture can protect the cylinder from attack.
What is PAS 24?
PAS 24 is a BSI specification called "Enhanced security performance requirements for doorsets and windows in the UK". It sets test methods and pass criteria for doors and windows intended to resist the kind of attack used by a casual or opportunistic burglar. Crucially, it tests the whole doorset rather than just the lock.
BSI withdrew the 2016 edition in September 2022, and products are now certified to PAS 24:2022. If a door company quotes an older edition, ask whether the product has been retested.
PAS 24 matters most for new homes. GOV.UK's Approved Document Q is the statutory guidance on security in new dwellings in England, and supports a building regulations requirement that "reasonable provision must be made to resist unauthorised access to any dwelling". For a replacement door on an existing home, a PAS 24 certified doorset is still a sensible benchmark to ask for.
What do TS 007 star ratings mean?
TS 007 is a Door and Hardware Federation specification for replacement cylinders and security hardware. It uses a star system, and the stars add up:
- 1-star cylinder: a security cylinder, but the MLA warns it has not passed a snapping test, even if it is sold as "anti-snap" or "snap-resistant".
- 2-star handle or escutcheon: security door furniture designed to protect the cylinder.
- 3-star cylinder: a cylinder tested against snapping that provides the protection on its own.
The MLA's minimum recommendation against lock snapping is a total of three stars. You can get there with a 3-star cylinder, or with a 1-star cylinder protected by a 2-star handle or escutcheon. Look for the Kitemark logo, usually on the face or side of the cylinder, which shows the product has been tested by a third party rather than only by its manufacturer.
What is Sold Secure SS312 Diamond?
SS312 is a Sold Secure test specification for lock cylinders. Sold Secure describes SS312 Diamond as a high-level specification that addresses the current methods used by criminals. Secured by Design notes that it is based on BS EN 1303:2015 and the general vulnerability assessment from BS 3621, with extra requirements on top.
According to the MLA:
- Diamond is the highest grade a lock cylinder can achieve, and is deemed equivalent to a Kitemarked 3-star cylinder for building regulations purposes.
- The lower SS312 Gold grade is treated as equivalent to a 1-star cylinder, so it should be paired with handles or escutcheons approved to SS301.
- SS312 Diamond currently applies only to euro profile cylinders.
The MLA's advice is to choose an SS312 Diamond cylinder where you can, and if not, at least a Kitemarked TS 007 3-star cylinder.
How do the standards compare?
| Standard or scheme | Who runs it | What it covers | What to look for |
|---|---|---|---|
| PAS 24 | BSI | Whole doorsets and windows tested against opportunistic burglary | Certification to PAS 24:2022 for the complete door |
| TS 007 1-star | Door and Hardware Federation | Security cylinder, not snap-tested | Only use with a 2-star handle or escutcheon |
| TS 007 2-star | Door and Hardware Federation | Security handles and escutcheons | Pair with a 1-star or 3-star cylinder |
| TS 007 3-star | Door and Hardware Federation | Cylinder tested against snapping | Kitemark logo with three stars on the cylinder |
| SS312 Diamond | Sold Secure | Highest grade for euro cylinders | Sold Secure Diamond marking and listing |
| BS 3621 / PAS 3621 | BSI | Locks for external doors; PAS 3621 is the multipoint equivalent | Standard number on the lock case or paperwork |
| Police Preferred Specification | Secured by Design | Police accreditation for independently tested and certified products | Secured by Design logo and listing in its product search |
What is lock snapping and how do you prevent it?
Lock snapping is an attack on euro cylinders, which are found on most uPVC doors and many composite and aluminium doors. The burglar breaks the cylinder and then manipulates the lock. Because one cylinder operates every locking point on a multipoint lock, the MLA notes that the other locking points become ineffective once it fails.
To reduce the risk:
- Fit an SS312 Diamond or Kitemarked TS 007 3-star cylinder, or a 1-star cylinder with 2-star security furniture.
- Make sure the cylinder is the right size. The MLA says it should not protrude more than 3 mm from the handle, because the more it sticks out, the easier it is to attack.
- Check for genuine third-party approval rather than relying on "anti-snap" wording alone.
- Use a qualified locksmith, such as an MLA-approved locksmith, to measure and fit the cylinder.
What does Secured by Design accreditation mean?
Secured by Design is the official police security initiative in the UK. Its Police Preferred Specification accreditation is given to products that have been independently tested to a relevant security standard and certified by a UKAS-accredited certification body, or by an approved body such as Sold Secure or Thatcham. It also requires regular retesting and annual factory inspections. Secured by Design does not test products itself.
Secured by Design's locks guidance says euro cylinders on uPVC and composite doors should meet TS 007 or SS312 Diamond, and that these doors should be fitted with a multipoint lock meeting BS 3621. Its online product search lets you check whether a door or lock is accredited.
Frequently asked questions
Is a 3-star cylinder the same as SS312 Diamond?
No. They are different standards from different organisations. The MLA says SS312 Diamond is deemed equivalent to a Kitemarked 3-star cylinder for building regulations, and it describes Diamond as the highest grade a cylinder can achieve. Some cylinders hold both ratings.
Do I need a new door, or just a new cylinder?
If your door and frame are in good condition, upgrading a basic euro cylinder to a 3-star or Diamond-rated one is a relatively simple improvement that a locksmith can usually fit. If the door is old, damaged or poorly fitted, a PAS 24 certified doorset gives protection across the whole door.
How can I tell what cylinder I already have?
Look at the face and side of the cylinder for a Kitemark with stars or a Sold Secure marking. If you cannot see any marking, assume it is a basic cylinder and ask a locksmith to check.
Sources
- Secured by Design: Locks and associated hardware
- Secured by Design: Security standards explained
- Sold Secure: Why get your security products tested?
- BSI: PAS 24, enhanced security performance requirements for doorsets and windows
- Master Locksmiths Association: Lock snapping and prevention
General information only. Product ratings and standards are updated over time, so check current certification with the manufacturer, Secured by Design or Sold Secure, and ask a qualified locksmith or installer for advice on your own door.