The best locks to stop burglars are those tested to UK security standards: a TS007 3-star anti-snap euro cylinder on uPVC and composite doors, and a BS3621 5-lever mortice deadlock on timber doors. Both resist the attacks burglars use most.
Choosing the right lock is the single most effective thing you can do to lower your burglary risk. Most break-ins target the door, and most beat a cheap, unrated lock. This buyer’s guide explains what makes a lock secure, the top choices for each door type, and how to pick one with confidence.
What makes a lock secure against burglars?
A lock is secure when it is independently tested to resist real attack methods: snapping, bumping, drilling, and picking. Security ratings such as TS007, Sold Secure, and British Standard prove a lock has passed that testing, rather than just claiming to be strong.
Home burglary risk comes down to how easily a burglar can beat your weakest lock. The Office for National Statistics links around 70% of break-ins to door entry, and on uPVC doors the common attack is lock snapping. Lock snapping is breaking a euro cylinder in two to release the mechanism, and a cheap cylinder gives way in seconds.
A secure lock is built to defeat these attacks. Hardened pins resist drilling, sacrificial sections resist snapping, and security pins frustrate picking and bumping. The rating on the box is your shortcut to knowing which locks actually do this.
Which security ratings should you look for?
Look for TS007 3-star on euro cylinders, BS3621 on mortice locks, and Sold Secure Diamond on high-security locks. These marks come from independent testing bodies and tell you a lock resists forced entry, rather than relying on the manufacturer’s word.
| Standard | What it means |
| TS007 3-star | Cylinder resists snapping, bumping, drilling on its own |
| TS007 1-star + 2-star handle | Reaches full protection when paired together |
| BS3621 | British Standard for mortice and night latch locks, insurer-recognised |
| Sold Secure Diamond | Top grade from the Master Locksmiths Association scheme |
| Secured by Design | Police-backed approval for tested products |
Buying to one of these standards is the clearest way to choose a lock that genuinely stops burglars, and to keep your home insurance valid.
What are the best locks to stop burglars by door type?
The best lock depends on your door. Fit a TS007 3-star anti-snap cylinder to uPVC and composite doors, a BS3621 5-lever mortice deadlock to timber doors, and a BS3621 deadlocking night latch as a secondary lock. Each is the proven choice for its door.
- uPVC and composite doors: a TS007 3-star anti-snap euro cylinder, sitting flush, not proud. This is the most common upgrade and stops snapping.
- Timber front and back doors: a 5-lever mortice deadlock to BS3621, which most insurers require on final exit doors.
- Additional security on timber doors: a BS3621 auto-deadlocking night latch, used alongside the mortice lock.
- Patio and French doors: a rated multipoint mechanism plus a sash jammer for extra hold.
- Highest security: a Sold Secure Diamond cylinder, often with restricted keys to prevent copying.
“On the tools, the best value upgrade by far is a 3-star anti-snap cylinder,” says a Kingdom Locksmith Ltd. “It defeats the attack we see most, it is quick to fit, and it costs a fraction of what a break-in costs. We fit anti-snap cylinders more than any other security lock.” Quality anti-snap cylinders are the first upgrade we recommend for most UK homes.
How much do the best security locks cost?
Good security locks are inexpensive against the cost of a break-in. An anti-snap cylinder upgrade typically costs from around £80 to £150 fitted, and a BS3621 mortice deadlock is similar. High-security and restricted-key locks cost more but add key control.
| Lock | Typical UK cost (guide) |
| TS007 3-star anti-snap cylinder, fitted | £80–£150 |
| BS3621 5-lever mortice deadlock, fitted | £90–£160 |
| Sold Secure Diamond / restricted-key cylinder | £60–£150+ part, plus labour |
| BS3621 deadlocking night latch, fitted | £80–£150 |
| Locksmith labour, standard hours | £65–£96 per hour |
These are guide prices and vary by lock, door type, location, and time of day, so ask your locksmith to confirm before work starts. Set against the average burglary loss and repair bill, a rated lock is a small, worthwhile cost.
How do you choose the right lock?
Choose the right lock by matching a tested standard to your door type, checking the cylinder size so it sits flush, and confirming your insurer’s requirements. A locksmith can measure, recommend, and fit the correct lock in one visit, which removes the guesswork.
Start with your door material and your insurance policy, since many insurers name BS3621. Measure a euro cylinder before buying, because one that protrudes past the handle is easy to snap. If you want the highest security, ask about restricted keys that cannot be copied without authorisation.
Secured by Design and Sold Secure both list approved products, so you can cross-check any lock before buying. When in doubt, a locksmith’s advice ensures the lock suits your door and meets your cover.
Frequently asked questions
What is the most secure door lock in the UK?
For uPVC and composite doors, a TS007 3-star anti-snap euro cylinder is the most secure common choice. For timber doors, a BS3621 5-lever mortice deadlock. A Sold Secure Diamond cylinder offers the highest cylinder security.
Are anti-snap locks the best at stopping burglars?
On uPVC and composite doors, yes. Lock snapping is the most common attack on these doors, and a TS007 3-star anti-snap cylinder defeats it. Pair it with a reinforced frame for the best result.
Do I need a BS3621 lock for insurance?
Many UK insurers require a BS3621 lock on final exit doors. Check your policy wording. Fitting one keeps your cover valid and improves security at the same time.
What is the difference between TS007 1-star and 3-star?
A 3-star cylinder resists snapping, bumping, and drilling on its own. A 1-star cylinder needs a 2-star security handle to reach the same level of protection. Both routes are accepted.
Can a locksmith recommend the best lock for my door?
Yes. A locksmith can assess your door, measure the cylinder, and fit a tested lock that suits the door and meets your insurer’s requirements, usually in a single visit.
Choosing a lock that stops burglars for good
The best locks to stop burglars are the ones proven by independent testing: a TS007 3-star anti-snap cylinder on uPVC and composite doors, and a BS3621 deadlock on timber doors. Matching a rated lock to your door defeats the snapping, drilling, and forcing that burglars rely on. Acting now matters, because the right lock is far cheaper than recovering from a break-in. At Kingdom Locksmith Ltd, we recommend and fit anti-snap, insurance-approved, and high-security locks for homes and businesses across the UK, matched to your door and your policy. Make your home the hard target burglars avoid. Upgrade to anti-snap cylinders and lock burglars out for good.