The Crime Prevention Website


Most of the locks on replacement doors rely on a ‘euro' profile cylinder or ‘oval’ profile cylinder to operate the locking mechanism. In recent years there has been a steady increase in the numbers of burglaries where these cylinders have been attacked to gain entry.

The police and security industry have known about these problems for several years, but because in the early days the techniques were used rarely and were confined to only a few locations around the UK, these problems were deliberately not broadcast to the public at large for fear of making the problem a lot worse.  Instead, the security industry quietly and quickly developed measures to protect the cylinders from these attacks.

With the methods of attack now widely broadcast across the internet your need to upgrade your door locks and associated hardware has become a lot more important. Before we find out what you can do about it let's first look at these attacks in a little more detail; something I wouldn't have written about a couple of years ago.

See DIRECTORY for anti-snap cyclinders

Cylinder snapping

The standard euro profile cylinder on your front door is essentially two cylinders together providing you with a keyway (keyhole) on both faces of the door.  If you live in a flat then your cylinder might have a thumb turn on the inner face instead of a keyway.  In the middle of the cylinder is a cam that turns when you insert and turn the key or the thumb turn and it is this cam that operates the locking mechanism.  The cylinder barrel is cast in one piece and the metal below the cam is quite thin.  This is the weak point. Having snapped the cylinder and removed it from the door the thief can turn the cam with a screwdriver to release the locking mechanism.

There are essentially four techniques used to snap the cylinder in half. There are no 'official' terms for these techniques, but I think my own nomenclature just about hits the spot.

Strike and Snap  On some doors the cylinder can protrude from the surface of the door by as much as 10mm.  By sliding a claw hammer sharply down the handle's faceplate onto the top of the cylinder the cylinder will often snap off after only one strike.  

Wiggle and Snap  Once again, if the cylinder is protruding it is possible to snap on a mole grip, wiggle the cylinder from side to side and it will eventually snap off.

Tool and Snap  This method is really the same as Wiggle and Snap except that a special cylinder snapping tool is used.  In essence the tool is a long bar with a cut out at one end that fits tightly over the cylinder profile.  The tool is often used by locksmiths when you've lost your keys and you're going to replace the cylinder.

Screw, Wiggle and Snap  (Sounds more like a dance!) Where the cylinder does not protrude a great deal a hardened 'concrete' screw can be turned into the cylinder to provide the necessary leverage point.

Peel and snap  Instead of using a screw the thief peels off the door handle plate to reveal the now protruding cylinder, which can be snapped off.  Sometimes the cylinder will snap off at the same time as the plate is peeled back.

Two of these techniques are ably demonstrated in this video on You Tube 


Lock 'bumping' involves the use of a special cut down key, which is inserted into the keyway.  Whilst applying a little turning force on the key it is tapped on the end. The energy travels down the key and makes the pins in the barrel jump up to the necessary positions to enable the key to turn the cam inside and unlock the door. Given a little practice the technique is quite achievable and sets of 'bump' keys are available to anyone off the internet - I've done it myself!  

Bumping (as a method used to commit burglary) reached our shores from Northern Europe around 2002 where, according to my contact in Denmark, it has been used by thieves for several decades. Of course, our locksmiths have known about the technique probably since the invention of the profile cylinder, because that's what locksmiths do; they try and overcome security devices so that they can open your door when you get locked out. The various locksmith associations around the world even have competitions to see who can 'bump' a lock the quickest!

Bumping dilemmas

Because bumping a cylinder leaves little or no evidence that the technique has actually been used to gain entry we are faced with two rather major dilemmas. The first one is concerned with how the crime is recorded by the police.  As a victim you could be telling the police that you definitely closed and locked all the doors and windows when you left the house, but the police officers will be scratching their heads thinking how then did the thief get in? With no obvious evidence to identify the point of entry who could blame them if they didn't believe you and surmised that the house was left insecure. In the end the crime report would probably record the point and method of entry as 'unknown', but this won't help you when it comes to making an insurance claim, which is the second dilemma.

The insurers will want to be convinced that you had secured all the doors and windows, as this is normally a condition of your cover, so how are you going to convince the insurers that the thief used a bump key? I have no doubt that insurers have come across this problem many times and have settled claims, but this dilemma is food for thought.  If this has happened to you please let us us know by clicking Feedback on this page at the top left of this page.

The extent of the problem

An added problem with bumping is that it has been difficult for the police to know how widespread the problem has become.  The limited analysis that has been conducted suggests that bumping is more common in newer housing developments where all the doors use a similar cylinder, which can be overcome using the same bump key.

Bumping appears to have been geographically concentrated suggesting limited learning exchange between thieves.  That being said it is clear that the police have considered bumping to be a growing problem, because they have worked closely with the industry and standards bodies encouraging the development of new standards for cylinders and attack resistant door hardware.

Solutions for Cylinder Snapping and Bumping

The Door and Hardware Federation and the Glass and Glazing Federation have produced a very useful guide for security and building professionals, installers and locksmiths entitled Meeting the new TS 007 security standard for replacement lock cylinders and protective door furniture.  In essence, the guide demonstrates how these persons can upgrade the security of a doorset by installing a fully resistant (Three Star) Kitemarked lock cylinder or combining a One Star cylinder with Two Star security hardware.

The full Technical Specification 007 Enhanced security performance requirements for replacement cylinders and/or associated security hardware can be viewed here.

There is also an alternative security standard for a kitemarked Three Star cylinder, which is SS312 Diamond Approved Standard, published by Sold Secure 

See DIRECTORY for anti-snap cyclinders

So, you can replace the existing euro-profile and oval cylinders in your doors with BSI Kitemarked, or SS312 cylinders that are resistant to bumping and snapping together with the door handle or other protective hardware.  Although you can do this work yourself you should employ a member of the Master Locksmiths Association if you are in any doubt.

If you have enhanced security doors that are certificated to PAS 24:2012 or the previous version of PAS 24, PAS 24: 2007 +A2: 2011, then the locking systems and door hardware will already be resistant to attacks on the cylinder and bumping. Look for the kitemark stamped on the face of the cylinder or on the key.

If your enhanced security doorset was certificated to an older version of PAS 24 then you should check the security of the locking mechanism, the cylinder and the hardware with the door supplier/manufacturer or a member of the Master Locksmiths Association. This is because the security of PAS 24 doorsets has improved a great deal since the first ones were manufactured in 1999.  For example, bump and snap resistant cylinders did not become a requirement of PAS 24 until 30th November 2008. A Master Locksmith will be able to check the components used in the door and possibly upgrade them.  That being said the best advice might be to upgrade the entire doorset, because although upgrading the cylinder and door handle might well improve the security of those elements, the overall security of the door assembly is the function of all the individual components working together. (At the time of updating this section (August 2014) a new PAS 24:2012 composite doorset bought in London cost £850 - installed)  

Be aware that you may invalidate the warranty on your doorset if you carry out work on it without first seeking agreement from the people who have issued the warranty.

USEFUL LINK  This link to The Master Locksmiths Association gives some excellent additional guidance about lock snapping 

Another solution developed to prevent cylinder snapping and bumping has been the introduction of a multi-point lock that uses the more traditional lever lock mechanism to drive it. A lock by the name of 'Vectis' can be found on the internet. Search 'Vectis Lock'.

Updated August 2014