· 7 min read
TS007 3-Star vs SS312 Diamond: Lock Security Standards Decoded
Compare TS007, SS312, Sold Secure and Secured by Design, then verify the exact product listing, door fit and any written requirement.
Guide topic
Lock Types and Security Ratings
What the markings on a lock mean, which standards apply to which lock, and what still has to be measured at the door.
8 guides in this topic · reviewed
What this topic covers
Most lock questions turn out to be two questions wearing one coat. The first is about the standard — what BS3621, TS007 or SS312 actually certify, and whether a marking on your lock means what a product listing implies. The second is about fit: whether a given lock can physically go into the door you have, in the condition that door is in today.
The guides in this topic separate those two. Standards are published, checkable and the same for everyone, so those sections cite the standards bodies and police-backed sources rather than my own opinion. Fit is specific to your door — its thickness, its backset, the gap it currently closes on — and that part is written as a list of things to measure or photograph, not as a conclusion.
If you are choosing between named products, start with what your door and any written insurance wording require, then narrow by certification, then by price. Doing it in the other order is how people end up with a certified cylinder that will not seat properly in the door it was bought for.
Where these guides stop
These guides can tell you what a standard certifies and which questions to ask. They cannot confirm what is fitted to your door, whether it was installed correctly, or whether a specific replacement will fit — those need the actual lock in front of someone.
Start here
What Is Lock Snapping and Does Your Coventry Home Have Vulnerable Locks?
Lock snapping is the failure mode most Coventry-area readers arrive asking about, and it explains why cylinder certification and mortice-lock certification are not interchangeable.
All 8 guides on lock types & security ratings
Guides to lock types, current standards, product markings and the checks needed at the actual door.
· 8 min read
5-Lever Mortice Deadlocks: Identification and Standards
Learn how lever count differs from BS3621 certification, how to inspect visible markings and why only the current written policy can establish an insurance requirement.
· 8 min read
Smart Locks in 2026: Are They Secure Enough for Your Front Door?
Review smart-lock access, power, override and compatibility questions before replacing or supplementing a mechanical front-door lock.
· 10 min read
Anti-Snap Locks Compared: Ultion vs ABS vs Yale Platinum vs Avocet
Compare named anti-snap cylinders by exact current certification, dimensions, documented features and compatibility with the complete door.
· 7 min read
Yale Locks vs Mortice Deadlocks: Which Does Your Front Door Need?
Compare nightlatches and mortice deadlocks, their different functions, and the door, escape and written-policy checks needed before changing either.
· 9 min read
BS3621 vs Anti-Snap vs Smart Lock: How Do They Differ?
Compare a mortice-lock standard, cylinder attack resistance and smart access features without treating unlike products as interchangeable.
· 7 min read
Euro Cylinder Locks Explained: Sizes, Types, and How to Measure Yours
Learn how euro-profile cylinders work, how to measure an installed cylinder and which fit, function and certification checks matter before replacement.
· 8 min read
What Is Lock Snapping and Does Your Coventry Home Have Vulnerable Locks?
Lock snapping is a recognised attack on some euro-profile cylinders. Learn what Police.uk and TS007 guidance establish, how to check the fitted system, and which certified upgrades may improve resistance.
When reading is not the answer
These guides explain the decision. If you already know what you need doing, the service pages below carry the published starting price, the scope each price assumes and the checks made before any work begins.
Lock UpgradeUpgrade your home security with British Standard BS3621 mortice locks, anti-snap cylinders, and independently certified options matched to the door and any written policy requirement.From £59 →Lock Repair & ReplacementDoor lock repairs and replacements for broken, worn or unreliable locks. Yale nightlatches, mortice locks and cylinders repaired or replaced across Coventry.From £59 →
Not sure which applies? The frequently asked questions cover scope, pricing and timing, and the full price list shows what each starting price includes.
Lock Types & Ratings — common questions
Click any question to see the answer
Which lock standard should I look for on a front door?
It depends on the lock, not the door alone. A mortice deadlock is usually assessed against BS3621, while a euro cylinder is assessed against cylinder-specific schemes such as TS007 or SS312. Check any written insurance wording first, because the policy names the requirement you actually have to meet.
Does a certified cylinder make the whole door secure?
No. A cylinder rating covers attacks on that cylinder. The door leaf, frame, hinges, glazing and the multipoint mechanism behind the handle all fail in their own ways, so an upgrade is only as useful as the weakest part it leaves untouched.
Can I tell what lock I have from a photograph?
Often partly. A clear photo of the lock face, the edge of the door and any kitemark or stamped text usually narrows it to a family of locks. Confirming the exact model, size and condition still needs measurement at the door.
Other guide topics
Home Security and Burglary PreventionWhere homes are actually entered, which upgrades address which entry point, and how to judge advice that sounds convincing.Understanding Locksmith Quotes and ChargesWhat a published starting price does and does not cover, and which questions make two quotes genuinely comparable.uPVC Door LocksHow multipoint doors fail, how to tell a repair from a replacement, and what to measure before anything is ordered.Locksmith EmergenciesWhat to do first when you are locked out, a key has snapped, keys are lost, or a door has been forced.Legal and Insurance RequirementsWhat a policy actually requires, how the lock standards differ, and where landlords and tenants stand on changing a lock.Seasonal Security GuidesThe security jobs that are worth doing at a particular time of year, and the failures that only show up in certain weather.Coventry and Warwickshire GuidesGuidance written around the housing stock, door types and local sources that actually apply across the Coventry area.
Or browse every locksmith guide in one list.
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