1 Star vs 3 Star Euro Cylinder: Which Do You Need?

If you’ve been looking at replacement euro cylinders you’ll have seen the little gold stars on the box — 1 star or 3 star. It isn’t marketing fluff. The rating tells you how well that cylinder stands up to snapping, picking, drilling and bumping, and it’s what most insurers now point to for uPVC and composite doors. Here’s what the ratings actually mean and how to pick the right one for your door.

What the TS007 stars actually test

TS007 is the kitemark scheme for euro cylinders, introduced after lock snapping became the quick way to force uPVC and composite doors. A cylinder is attacked with snapping, picking, drilling, bumping and manipulation, then rated:

The 1-star + 2-star-handle combination

Here’s the bit that catches people out: a 1-star cylinder behind a 2-star security handle meets the same standard as a 3-star cylinder on its own. The handle’s reinforced escutcheon covers the exposed part of the cylinder, so the pair resists snapping just as well. That gives you three sensible routes:

What doesn’t count: a 1-star cylinder with an ordinary, unrated handle. That pairing has no snap protection at the handle and is exactly the setup burglars look for on uPVC doors.

Why the cylinder is the whole game

Your door probably has a serious multipoint lock behind the handle — hooks, rollers, a deadbolt, all throwing into the frame. That mechanism is strong. But it does not decide who gets in. The cylinder does. Its only job is to control access to the mechanism: turn the correct key and the cam turns the gearbox; defeat the cylinder and the same gearbox opens for anyone.

That is why an unbranded, untested cylinder — or a certified one that has been fitted in the wrong size — makes the rest of the lock almost irrelevant. It can have the best locking system in the world bolted behind it; if the cylinder gives way with a cheap tool and a few minutes of practice, the door is open. No damage to the mechanism, no noise, no skill worth mentioning.

Wrong size is as bad as wrong lock

A cylinder that sits proud of the handle — even by a few millimetres — gives an attacker something to grip and lever. Anti-snap protection is designed around a flush fit. A certified cylinder fitted 5mm too long has thrown away much of what you paid for, which is why measuring both sides properly matters as much as the star rating on the box.

Not all kitemarks are the same

The BSI Kitemark tells you a sample of that cylinder was sent to an independent test house, attacked in set ways for set times — snapping, drilling, picking, bumping, plug extraction — and survived long enough to pass. It is a pass/fail on a specific test script. It is a good thing, and you should insist on it.

What it does not tell you: how well the cylinder is built, whether it will still be smooth and reliable in five winters, how many security features it has beyond the ones tested, or how consistently the factory matches the sample that was sent for testing. Two cylinders can carry the same 3-star mark and be very different products — different steel, different pin quality, different tolerances, different resistance to methods that were not on the test sheet. The mark sets a floor, not a ceiling.

• Same stars, different lock. The rating is the minimum a cylinder met on test day, not a measure of build quality or reliability.
• Brand carries the rest. Reputation, consistent manufacturing, spare keys that actually match, and a warranty someone will honour.
• Fit finishes the job. Correct length, correct handle, correctly aligned door. A great cylinder badly fitted is a mediocre lock.

Why we are fussy about where locks come from

Over many years we have built relationships with most of the lock suppliers in the UK, and we have cherry-picked the few whose products we are certain about. Before a cylinder earns a place in our van, we test its security claims ourselves — we attack it the way a burglar would and see whether it holds. Only the ones that pass become the locks we fit every day, so by the time one goes on your door we already know exactly how it behaves. We do not stock locks from Amazon or the off-the-shelf ranges in DIY stores, for exactly that reason: the box may say the right things and the lock may not.

The practical upshot for you: when we fit a 1-star or 3-star cylinder, it is a brand we have tested and use daily — one we would put on our own door — in the right size, behind the right handle, on a door that closes properly. That combination — not the sticker alone — is what keeps people out.

Why lock snapping made this necessary

Standard euro cylinders have a weak point at the fixing screw, roughly where the cylinder sits flush with the handle. One sharp strike with a wide-bladed tool snaps it there in seconds, giving direct access to the mechanism — no picking, no drilling, no noise. For years it was the single most common way uPVC doors were forced.

Anti-snap cylinders have a sacrificial section that breaks away cleanly while the working part of the lock stays intact, so the door remains secure after an attempt. That’s the core difference the star rating buys you.

Which one do you actually need?

For most uPVC or composite front or back doors:

• A 3-star anti-snap cylinder if you want the premium option — the most protection in a single part, especially on doors visible from the street or a side passage.
• A 1-star cylinder as a good mid-range choice — pair it with a 2-star security handle to reach the same 3-star-equivalent standard.
• A 2-star security handle as well when the door is ground-floor, faces a public path, or has been targeted before.
• Get the length right — a cylinder sticking out even a few millimetres past the handle gives an attacker something to grip, whatever the star rating. It should sit flush or barely proud, measured from both sides.

A 1-star cylinder on its own is a perfectly good mid-range choice — kitemarked, anti-drill, anti-pick and anti-bump, with a sacrificial snap line — and on plenty of doors it’s the sensible spend. Add a 2-star handle when you want the full standard without changing the cylinder, or go straight to 3-star when you want the premium option and the simplest answer for your insurer.

The insurance angle

Check your current cylinder in two minutes

1. Look at the cylinder face — the metal end visible at the handle — for a stamped 1★ or 3★ or the TS007 kitemark.
2. No rating visible at all? It’s probably an older, unrated cylinder and worth reviewing.
3. Measure how far it sits proud of the handle on both sides. More than 2–3mm should be addressed regardless of the rating.
4. Not sure what you’re looking at? A photo is usually enough for a locksmith to tell you what you’ve got and what an upgrade costs.

When to call a locksmith

Swapping a euro cylinder is one of the most cost-effective upgrades you can make to a uPVC or composite door, and it’s usually quick once the size is confirmed. Our lock replacement and upgrades service covers exactly this — measuring the door properly, fitting a 3-star anti-snap cylinder (with a matching security handle if you want belt and braces) and checking the rest of the door while we’re there.

Had a break-in and need locks assessed urgently? Our after-burglary service and emergency locksmith team can attend quickly.

Frequently asked questions

Related: Lock Replacement & Upgrades · uPVC & Door Lock Repair · After Burglary Service