Your Guide to the Security Rating of Door Locks

When you look at a lock's packaging, you will find references to BS3621, TS007 3-star, PAS 24, Sold Secure and Secured by Design. These are not interchangeable marketing labels — each covers something specific and each matters in a different context. This guide explains what each standard covers, what your insurer is likely to require, and how to make the right choice for your front door without wading through technical documents.

BS3621: The Insurance Standard for Deadlocks

BS3621 is the British Standard for thief-resistant lock assemblies, published by the British Standards Institution. It covers mortice deadlocks, cylinder deadlocks and rim deadlocks, setting minimum performance requirements for resistance to picking, drilling, sawing and manipulation with common hand tools.

This is the standard specified by most UK home insurance policies for external doors. If your policy requires BS3621-compliant locks and your current locks do not meet it, you may find a claim reduced or refused following a forced entry. The standard applies to the lock assembly as tested — a BS3621-rated cylinder fitted to a substandard lock body does not produce a BS3621-compliant door lock. Check the product carries the full certification, not just a component of it.

A five-lever mortice deadlock meeting BS3621, fitted correctly into a good timber door with appropriate screws into the structural frame, is still a solid baseline choice for the majority of South London timber front doors.

TS007 3-Star: The Current Benchmark for Cylinders

TS007 is a more recent and comprehensive specification developed by the Master Locksmiths Association and the Lock Manufacturers Association. Unlike BS3621, which tests the lock body, TS007 tests the complete door hardware assembly — the cylinder, the lock body and the external escutcheon plate together. This matters because the most common contemporary attack vector, cylinder snapping, targets the cylinder-escutcheon interface, not the lock mechanism itself.

A TS007 3-star rating (the highest level) means the complete assembly has been independently tested against attack methods including cylinder snapping, picking, drilling and bumping. Most reputable cylinder manufacturers — Ultion, Mul-T-Lock, Yale Superior — now produce cylinders designed to meet TS007 3-star when paired with the correct escutcheon. If you are upgrading a euro cylinder on a uPVC or composite door, specifying a TS007 3-star assembly is the current industry recommendation for South London front doors.

PAS 24: The Door Set Standard

PAS 24, published by the British Standards Institution, sets enhanced security performance requirements for door sets — the door leaf, frame, glazing, hinges and lock hardware tested together as a complete unit. A PAS 24-certified door has been attacked using defined manual methods including sustained force, drilling, levering and manipulation, and has resisted those attacks for the required time periods.

PAS 24 is most relevant when replacing a complete door rather than upgrading the lock on an existing one. It is the performance standard underpinning Secured by Design approval for residential door sets, and it is increasingly referenced in mortgage lender requirements for new builds. The Secured by Design product database allows you to verify whether a specific door set is certified before you buy.

Secured by Design: The Police-Backed Accreditation

Secured by Design is a UK police-led accreditation scheme operated through the association of chief police officers. Products approved under the scheme must meet or exceed PAS 24 (for door sets) or other relevant standards depending on the product category, and must be installed according to the manufacturer's specification to retain their certified status.

Secured by Design approval is worth looking for on any major purchase — replacement front door, composite door or complete security system — because it confirms the product has been independently tested rather than self-certified. The scheme covers doors, windows, padlocks, cylinders, alarms and access control systems. For residential applications, the scheme's Police Preferred Specification label indicates products meeting the performance threshold the police recommend.

Sold Secure: The Rating System for Padlocks and Portable Security

Sold Secure is the UK's principal testing body for portable security products — padlocks, chains, cycle locks, door chains and related hardware. It grades products at Silver, Gold and Diamond levels based on the time and tool types required to defeat them. Sold Secure Diamond is the highest grade and corresponds to resistance against heavy-duty angle grinders and large bolt cutters.

For outbuilding and garage padlocks, most insurers specify Sold Secure Gold or Diamond as a minimum. For cycle security, Diamond is standard for any high-value bike. Sold Secure grades are independent from the brand's own claims and verified through physical attack testing, making them a reliable guide when comparing padlocks at different price points.

How to Read Lock Packaging Before You Buy

• Look for the specific standard number (BS3621, TS007 3-star) not just a description like "high security."
• Check that the rated product is the complete assembly you are buying, not just one component of it.
• For cylinders on uPVC doors, confirm the TS007 star rating applies to the cylinder, escutcheon and lock body combination, not the cylinder alone.
• Verify Secured by Design or Sold Secure claims through the respective organisations' websites, not just the packaging.

If you are unsure which rating your insurer requires, call them directly before purchasing. The locksmith who fits the lock can also advise — any competent professional working in Sutton or South London will be familiar with current insurer requirements.

Frequently Asked Questions

Can I upgrade just the cylinder to make my lock BS3621 compliant?

Not automatically. BS3621 is tested as a complete lock assembly. Fitting a quality cylinder into a substandard lock body does not produce a certified assembly. If you need full BS3621 compliance, the entire lock unit should meet the standard. Your locksmith can advise whether your current lock body qualifies.

What is the difference between TS007 1-star, 2-star and 3-star?

TS007 grades are assigned to the complete door hardware assembly tested together. A 1-star rating covers the cylinder alone. A 2-star rating covers cylinder plus escutcheon. A 3-star rating covers cylinder, escutcheon and lock body together — the most comprehensive level, and the one recommended for front doors.

Do I need PAS 24 for my existing front door?

PAS 24 applies to complete door sets, so it is most relevant when replacing a whole door. If you are keeping the existing door and upgrading only the locks and cylinder, TS007 3-star and BS3621 compliance are the standards to focus on for most UK insurers.

Is a Secured by Design lock always better than a non-SBD equivalent?

Secured by Design approval confirms independent testing against a defined specification. It is a meaningful quality marker, not just a marketing claim. However, some non-SBD products from reputable manufacturers also meet high performance standards — check the underlying test results (TS007, BS3621) rather than relying solely on the SBD logo.