Best 5 Lever Mortice Lock for Home Security: 2025 Expert Review
DR Joinery
Expert Joiner & Door Installation Specialist
Choosing a lock might seem like a small detail, but for anyone living in York's older terraces or semi-detached homes, it is the first line of defence. More importantly, if your lock isn't up to British Standard (BS3621), your home insurance policy might be invalid without you even realising it.
I often attend jobs where a homeowner has bought a cheap lock from a generic hardware store, only to find the mechanism grinds after a month or the brass plating flakes off in the damp Yorkshire weather. Security is not the place to cut corners, but that doesn't mean you need to spend a fortune.
In this review, I'm looking at three mortice locks I fit regularly. Whether you are upgrading a front door deadlock or fitting a full sashlock to a back door, these options meet the strict requirements of modern insurance policies whilst suiting traditional timber doors.
Live in York?
Unsure if your locks meet insurance standards?
We can upgrade your security with professional fitting.
Specs vs. The Real World
The Spec: "BS3621 Certified"
"If a lock has the Kitemark, it is invincible against thieves."
The lock is only as strong as the wood it is fitted into. In older softwood doors found in York, the frame often splits before the lock breaks. A high-quality lock must be paired with a solid frame and decent strike plate installation.
The Spec: "Anti-Pick & Anti-Drill"
"Thieves will spend time trying to pick the lock or drill the cylinder."
In my experience, burglars rarely pick locks; they kick doors. The 20mm bolt throw and the strength of the screws into the frame are far more important for physical resistance than the picking complexity.
My Top 3 Recommendations
Three options to cover different needs and budgets
ERA Fortress 261-31A, 2.5-inch/ 64mm 5 Lever Maximum Security Mortice Deadlock - Brass Effect
ERA
This is a classic 'deadlock' – meaning it has no latch for a handle, just the bolt. It is the industry standard for adding security to a front door that already has a nightlatch (yale lock). It offers full BS3621 protection without unnecessary frills.
The Good
- Full insurance approval (BS3621)
- Hardened steel plates protect against drilling
- 20mm bolt throw prevents the frame from being spread to bypass the lock
The Bad
- Brass effect finish is functional but less durable than solid brass
- Requires precise chiselling; the case is quite boxy
Installer Tip:
This is a 64mm (2.5 inch) lock. Before buying, check where your door style sits. If you drill too close to the edge of the glass rebate on a glazed door, you'll weaken the timber. Measure from the door edge to the centre of the keyhole on your old lock first.
Priced at £17.79 at the time of writing
Check Price on AmazonERA Fortress BS 3621 2.5-inch/ 64mm 5 Lever Maximum Security Mortice Sashlock - Brass Effect
ERA
Unlike the deadlock above, this is a 'sashlock', meaning it includes a latch for handles. This is the ideal choice for back doors or new front doors where you want handle operation. The build quality on the Fortress series is excellent, with a reassuring 'clunk' when locked.
The Good
- Combines latch and deadlock in one secure unit
- Laminated hardened steel bolt is extremely tough
- Reversible latch bolt allows it to fit left or right-hung doors
The Bad
- Mortice (hole) required is larger than for a deadlock
- Installation takes longer due to lining up handles and lock perfectly
Installer Tip:
When cutting the mortice for this, be careful not to remove too much wood from the door stile (the vertical timber). If you cut the pocket too loose, the lock forces are transferred poorly to the door. I always fit these with a snug fit, piloting screw holes to prevent splitting the grain.
Priced at £18.34 at the time of writing
Check Price on AmazonYale British Standard 5 Lever Mortice Deadlock, High Security, Visi Pack
Yale
Yale is perhaps the most recognised name in locks. I categorise this as 'problem-solving' because it carries the 'Secured by Design' police approval. If you are worried about voiding strict insurance policies, fitting a Yale removes any doubt. It is also very easy to source spare keys locally.
The Good
- Trusted brand name instantly recognised by insurers
- Secured by Design approved (Police preferred specification)
- Keys are easily cut at any high street cobbler
The Bad
- The faceplate corners are square, requiring sharp chisel work (some DIYers struggle with this compared to rounded radius plates)
- Keyhole escutcheons supplied can be a bit basic
Installer Tip:
If you are replacing an old lock, check the 'backset' (distance from edge to keyhole). Older locks in Victorian properties often have unusual sizes (like 3 inches). This is a standard 2.5 inch (64mm). If your old hole is further back, you might need a larger lock or to fill and re-drill, which is a skilled joinery job.
Priced at £16.99 at the time of writing
Check Price on AmazonFrequently Asked Questions
What is the difference between a deadlock and a sashlock?
Why must I have a BS3621 lock?
Can I fit a mortice lock myself?
What size lock do I need, 64mm or 76mm?
Need Professional Internal & External Door Fitting?
Our team at DR Joinery specialises in Internal & External Door Fitting across York.
Get a free quote for professional installation.
View Our Internal & External Door Fitting Service