Is PAS3621 the same as BS3621?

Not exactly. PAS3621 is a newer, broader specification that covers both traditional 5-lever mortice deadlocks (like BS3621) and euro cylinder mortice deadlocks. The security testing is equivalent, but most insurance policies still specifically reference BS3621. If your policy says BS3621, check with your insurer whether PAS3621 is accepted — in most cases it will be, but it is worth confirming in writing.

Do I need BS8621 locks in my rental property?

If your property is an HMO (House in Multiple Occupation), then yes — fire safety regulations require keyless egress from final exit doors and individual rooms. For standard single-let rentals, BS8621 is not legally required but is increasingly recommended as best practice. Many Coventry letting agents now request BS8621 as standard. The cost difference over a standard BS3621 lock is minimal — typically an extra £10-15 per lock.

How can I tell if my mortice deadlock meets BS3621?

Look at the faceplate — the metal strip visible on the edge of the door when it is closed. A genuine BS3621 lock will have the BSI Kitemark (a heart-shaped symbol) and the standard number stamped into the metal. If there is no Kitemark, the lock has not been independently certified regardless of what the packaging or seller claimed. If you are unsure, call me on 07735 336175 and I will check it for you for free.

Can a lock meet both BS3621 and BS8621?

Yes. Several manufacturers make mortice deadlocks that are dual-certified to both BS3621 (thief resistance) and BS8621 (keyless egress). These locks have a thumbturn on the inside for emergency exit but still meet the full security testing requirements of BS3621. They cost slightly more than a standard BS3621 lock but give you both insurance compliance and fire safety. I fit dual-certified locks from around £89 including fitting.

PAS3621, BS3621, and BS8621: Which Lock Standard Applies to Your Door?

Three British Standards, three different purposes. Here is a plain-English guide to the differences — and which one your insurance policy is actually asking for.

PAS3621 vs BS3621 vs BS8621: What Every Homeowner and Landlord Needs to Know

If you have ever tried to read your home insurance policy or looked into upgrading your locks, you have probably come across at least one of these three standards. They look almost identical — just a few letters and numbers apart — but they mean very different things for your security, your insurance, and in some cases, your legal obligations.

I am Ross, a local locksmith in Coventry, and I deal with these standards every single day. Whether I am fitting locks to a Victorian terrace in Earlsdon or upgrading a student HMO in Stoke, knowing which standard applies can be the difference between a valid insurance claim and a rejected one.

Let me break all three down in plain English.

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BS3621: The Standard Your Insurance Almost Certainly Means

BS3621 is the British Standard for thief-resistant locks. It has been around since 1980, updated several times, and it is the standard that the vast majority of UK home insurance policies reference by name.

What BS3621 Actually Requires

A lock that meets BS3621 must:

Be a **5-lever mortice deadlock** (the type that sits inside the edge of a wooden or composite door)

Resist picking, drilling, and forcing for a defined period under laboratory testing

Have a **minimum of 1,000 key differs** (so your neighbour cannot open your door with their key)

Have a **BSI Kitemark stamped on the faceplate** — the metal plate visible on the edge of the door when it is closed

That last point is important. A lock can claim to be "to BS3621 standard" all day long, but unless it carries the actual BSI Kitemark, it has not been independently tested and certified. I see this all the time — cheap locks sold online as "BS3621 equivalent" that would not pass the test.

When BS3621 Applies

**Wooden front doors** — this is the main use case

**Composite doors with a mortice deadlock** (less common now, as most composite doors use euro cylinder multipoint locks)

**Any door where your insurance policy specifically requires BS3621**

If your home has traditional wooden doors — and many older properties across Coventry do, from Chapelfields to Coundon — then BS3621 is almost certainly what your insurer expects on your final exit doors.

I fit BS3621 mortice deadlocks from £79 including the lock and labour. You can see full pricing on our [prices page](/prices).

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PAS3621: The Updated Standard Most People Have Never Heard Of

PAS stands for **Publicly Available Specification**. PAS3621 was introduced to update and broaden BS3621, and the key difference is simple: **PAS3621 allows euro cylinder mortice deadlocks**, not just traditional lever mortice deadlocks.

Why This Matters

BS3621 was written in an era when almost every front door in Britain was wooden and fitted with a lever mortice deadlock. But door technology has moved on. Many modern composite doors and some timber doors now use a mortice lock body with a euro cylinder rather than levers.

PAS3621 recognises this. It applies the same security testing standards as BS3621 but extends them to cover:

Traditional 5-lever mortice deadlocks (same as BS3621)

**Euro cylinder mortice deadlocks** (the cylinder must also meet its own security standard)

Locks that combine both mechanisms

The Insurance Problem

Here is where it gets tricky. Most insurance policies still reference **BS3621** specifically. Very few have updated their wording to include PAS3621. This is slowly changing, but right now, if your policy says "BS3621" and your lock only meets PAS3621, there is technically a gap.

In practice, I have not seen an insurer reject a claim solely because a lock met PAS3621 rather than BS3621 — the security level is equivalent or better. But if you want to be completely safe, either:

Fit a lock that meets **both** standards (most quality 5-lever mortice deadlocks from brands like ERA, Union, and British Standard do)

Call your insurer and ask them to confirm PAS3621 is acceptable

Call me on 07735 336175 and I will check what you have and what you need

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BS8621: The Accessibility Standard That Could Save Your Life

BS8621 is fundamentally different from the other two. It is not primarily about keeping burglars out — it is about **letting people get out safely**.

What BS8621 Requires

A BS8621 lock allows **keyless egress from the inside**. In plain English: you can open the door from inside without needing a key.

With a standard BS3621 mortice deadlock, you need a key to lock and unlock the door from both sides. If there is a fire and you cannot find your keys, you are trapped. BS8621 solves this with a thumbturn or similar mechanism on the inside.

When BS8621 Is Required

**HMOs (Houses in Multiple Occupation)** — Coventry has a huge number of HMOs, particularly around the university areas of Stoke, Hillfields, and Gosford Green. Fire safety regulations mean individual room doors and final exit doors in HMOs should allow keyless egress

**Rental properties** — while not always legally mandated, many landlords and letting agents now fit BS8621 locks as best practice, and some local authority licensing conditions require it

**Properties where elderly or vulnerable residents live** — if someone cannot easily locate or turn a key in an emergency, a thumbturn lock can be life-saving

The Security Trade-Off

There is an honest trade-off here. A thumbturn on the inside means that if a burglar can reach through a letterbox or broken glass panel near the door, they could potentially turn the thumbturn and open the door from inside.

Good BS8621 locks mitigate this with:

**Anti-thumbturn features** that require a deliberate grip rather than a simple push

**Positioning** that makes it hard to reach from a letterbox

**Combining with a letterbox restrictor** to prevent fishing attacks

I fit BS8621 locks regularly in Coventry HMOs and always discuss the letterbox security at the same time. If you are a landlord needing HMO-compliant locks, see our [lock change service](/services/lock-change) or call me directly on 07735 336175.

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How to Tell Which Standard Your Lock Meets

This is one of the most common questions I get, so here is a quick guide:

For Mortice Deadlocks (BS3621 / PAS3621)

**Look at the faceplate** — the metal strip on the edge of the door. A certified lock will have the **BSI Kitemark** (a heart-shaped symbol) stamped into it, along with the standard number

**Check the key** — BS3621 keys are chunky with a complex bit pattern. If your key is thin and simple, the lock probably does not meet the standard

**Count the levers** — remove the lock or look at the key. BS3621 requires 5 levers minimum. A 3-lever lock (common on internal doors) does not meet the standard

For BS8621

Look for the **BSI Kitemark with BS8621** on the faceplate. The lock will have a thumbturn or push-to-exit mechanism on the inside face. If your lock requires a key to open from both sides, it is not BS8621.

Not Sure?

Honestly, the easiest way is to call me. I offer a **free security check** across Coventry and the surrounding areas — I will look at your locks, tell you exactly what standard they meet (or do not meet), and advise on whether you need to upgrade for insurance or legal compliance. No obligation, no hard sell. Call 07735 336175 or check which [areas we cover](/areas).

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Which Standard Do You Actually Need?

Here is my practical advice based on hundreds of jobs across Coventry:

SituationStandard Needed

|---|---|

Homeowner with wooden front doorBS3621 (check your insurance policy)

Homeowner with composite/uPVC doorUsually TS007 3-star cylinder — see our post on [insurance-approved locks](/blog/insurance-approved-locks-explained)

Landlord with standard rentalBS3621 on wooden doors, consider BS8621 for safety

Landlord with HMOBS8621 on final exit doors and individual room doors

Student rentalBS8621 strongly recommended (fire safety)

If you are a Coventry landlord managing multiple properties, I offer discounted rates for bulk lock changes. Whether it is the September student turnover or a mid-year tenancy change, call me on 07735 336175 and I will give you an honest quote.

For more on the insurance side of lock standards, read our detailed guide on [whether your insurance will pay out with non-compliant locks](/blog/insurance-payout-lock-standards). And if you want to understand your obligations as a landlord around lock changes between tenants, I have covered that in our guide to [changing locks between tenancies](/blog/landlords-change-locks-between-tenants).