The Crime Prevention Website


For property marking to have any chance of deterring the thief he’s got to be able to see the mark or know that it is marked in some way.  The latter is achieved through the use of warning signs on the building and or labels on individual items of property.  There are lots of methods that can be used to mark your property, which are described below.    

Using the postcode

Although regarded as a ‘bit old hat’, writing, stamping or engraving the security postcode onto items of property may be useful as a  basic  deterrent in some circumstances.  Although I would encourage you to use a more advanced marking system, if you don’t want to spend money then at the very least you should use your security postcode.

Here’s how to work out your security code:

Each property in the UK has a postcode.  Large buildings, such as an office block, often have their own unique postcode whilst smaller buildings, such as houses, will share a postcode with perhaps 20 others.  Using the postcode followed by the house or flat number, or the first two letters of the name of the house (if there isn’t a number) gives you a unique ‘security’ code.

Street address:    50 Constable Close

Postcode:            XY5 2RS

Security code:    XY52RS50 

Street address:    Flat 49 25 Constable Close

Postcode:            XY5 2RB

Security code:     XY52RB22/49

Street address:   Gable End Constable Close

Postcode:            XY5 2RS

Security code:     XY52RSGA 

If you’ve marked your property and you move address, you just put an ‘X’ at the end of the code and put the new one on it.  If you sell it then you’ll have to encourage the new owner to put their security postcode on it and then I’m afraid it all starts to get a bit messy. 

Author’s thoughts

I’ve used the postcode to mark my outside garden furniture.  I used an indelible ink pen and chisel to mark the bottom of each item of furniture with very large numbers and letters.  A bit crude I know, but I’m never going to sell the furniture or move and I don’t look at the undersides!  Removing these marks is of course possible, but would require considerable time and effort.

UV Pens

Back in the 1980s, when property marking was first promoted by the police service, we gave away a lot of UV pens and asked you to mark your valuables with your postcode (as above).  The problem with UV ink is that in direct sunlight it fades away, and after a few months it will be there no longer!  This problem was known about back then and we used to ask people to mark things on their undersides so that the mark would last longer.  Frankly, we’ve come a long way since then and whilst I wouldn’t say ‘don’t use UV pens’ I do think their use is rather limited.  I would recommend using one of the more advanced marking methods as described below.   


Whilst you can use a hand or electric tool to etch a postcode or a name (or whatever) into the surface of an item of property it is far better to use a professional system that meets the police approved standards. (See Standards for property marking products and services )  Professional etching systems have been available for perhaps 20 years or more and the chances are you will have seen the marks on office equipment on many occasions.   

Chemical etching systems provide you with tamper resistant adhesive stencils that include a unique serial number and the contact number of the secure database register.  You simply stick the tamper resistant stencil onto the item you want to mark and then apply an etching compound over the cut outs.  The compound chemically reacts with the surface of the product and permanently marks it with the unique code and database contact number.  If you try to remove the label the etched mark will remain and it’s very difficult to remove it.

Companies provide many styles of stencils and warning labels and produce different compounds to use on different materials.  Motor vehicle windows and engine parts can be etched using similar systems or by laser cutter. 

Author’s thoughts

There are limitations with etching as it’s not suitable for things like jewellery or property that would be devalued if you marked it in this way.  That said, I still like this form of marking because it can be easily seen by the thief who may be deterred from stealing it and likewise a visible mark provides instant information to the police when they have stopped someone in the street, enabling them to conduct a quick check with the manufacturer’s database.   

Microdot, chemical and DNA marking

The following forms of marking are good for all types of property and especially those that are very small.  Choose a system and secure database register that meets the police recognised standards. (See Standards for property marking products and services )  The advantage of synthetic DNA, microdot and other chemical marking is that it can be used to mark just about anything without damaging it.  It’s extremely quick to apply and also just about impossible to remove.  The DNA or chemical mark and the accompanying UV tracing dye used in spray and gel versions of the various products will remain on skin and clothing for many weeks adding to the chances of detection.

The cost of using these systems is determined by how much of it you use and whether or not you have to pay to use the manufacturer’s database, so it’s worth reading the manufacturers’ sites in some detail in order to find the right product for you.  Each manufacturer has different procedures for you to follow when you move or sell an item that you have marked.

Importantly these marking systems are supplied with tamper resistant stickers and signs that warn the potential thief that the property he might steal has been marked.  Without visual warnings the system will not act as a deterrent. 


Microdots are very tiny discs that are held in an adhesive solution in a container that resembles a nail varnish bottle.  You simply apply a small amount of the solution with a brush or spatula to the surface of the product and the job is done.  Each microdot carries a unique code and database contact telephone number that has been printed on them many times.  These microdots can just about be seen by the naked eye, but the detail printed on them can only be viewed under a microscope (hand held, pen sized, scopes with lights can be supplied).  The unique codes on the discs can then be checked against a database to identify the owner.  The solution holding the microdots will also have a dye that will show up under UV light. 


Synthetic DNA, as the name suggests, is manufactured DNA and one of its most exciting uses is in the world of crime prevention and detection.

The manufacturers of asset marking systems use uniquely coded synthetic DNA in a variety of substances with the aim of marking property and or the criminal.  Each of the substances will also carry a tracer dye that will show up under UV light.  When prisoners and property arrive at police stations they are viewed under UV light as a matter of course.  If the property or the arrested person’s skin and or clothes fluoresce under the UV light then samples will be taken from them and submitted for analysis.  As each batch of DNA is uniquely coded the police will be able to link the criminal to the scene of the crime and be able to establish who owns the recovered property.  Some manufacturers also include microdots in the various applications.  These provide details of the database where the product’s owner can be identified, making identification even quicker.   

Synthetic DNA (and other chemical marking systems) is used in the following ways:

  • In water based adhesives so you can paint it onto individual items of property

  • In water based sprays.  The sprays are either delivered automatically in conjunction with an intruder alarm or some other movement detection device or manually by hand held sprayer or by a device set off by a person during an incident, such as a robbery in an off licence.  There’s even a door chain device that sprays a caller should the caller attempt to force the door chain

  • In grease that is smeared over valuable outdoor items, such as lead roofs and copper piping

  • In gel that is smeared on indoor items, such as door and window handles and cash tills

Managing Director                                                                    Redweb Technologies

RedWeb Technologies are the leading providers of Advanced Molecular Taggent Solutions (AMTT) and GPS tracking solutions. RedWeb Technologies are based in Rugeley, work with the police, utility companies, private investigators and security companies. Our products are “Secured by Design” approved and we have trackers that are Thatcham accredited. We also have British Standard rated analysis laboratories to give irrefutable evidence in order to secure convictions and we are the only forensic fluid provider to hold this standard.

Our forensic tagging products provide irrefutable evidence linking criminals to crime scenes helping to improve conviction rates and provide a strong deterrent to thieves. We have products that mark offenders when they come into contact with stolen goods and on entry into buildings. Each batch of AMTT has its own unique code and this directly connects them with the scene of the crime. This technology is also being used to combat metal theft in many areas and we have many case studies demonstrating the successes we have had using our AMTT Technology.

Our GPS trackers have been used in many sting operations in forces up and down the UK and have helped reduce crime in these areas. RedWeb Technologies has many different types of trackers available for different situations and deployments. We supply the tracker hardware solutions for: lone worker protection, vehicle, plant, high value products and farm machinery tracking and recovery. We can also supply covert trackers and also fit them into assets for sting operations such as bike seats, sat navs, laptops and iPads. RedWeb's GPS Tracker options allow you to view the whereabouts of your tracker by mobile phone or by computer and to track individual or multiple devices. 

For more information call us on 0800 157 7246 to find out how you can deter theft from your organisation or you can visit our website:

Other chemical marking systems

There are other marking systems on the market that use metal based inert chemical compounds instead of DNA.  Each batch of the product is unique to the owner and includes a UV traceable dye and therefore the property marked with it and people sprayed by it can be forensically linked to the scene of the crime in the same way as the DNA based products. 

Property tagging

Property tagging is all about the use of an electronic transponder (also known as a ‘tag’, ‘RFID chip’ or microchip) that is small enough to be hidden somewhere on an item of property.  There are two main types of transponder; a rigid type which is the size of a grain of rice and the flexible flat type that resembles the alarm tags you’ll often find on electrical products.  Each transponder possesses a unique identification code that can be read by a hand held scanner used by the UK police services.   As with the property marking systems above, this method of tagging will not act as a deterrent unless the potential thief knows that the property has been tagged and so the systems are also supplied with tamper resistant stickers. Some manufacturers also supply the transponders with an additional marking system using, for example, microdots or stencil labels for manual or chemical etching.  This type of system is commonly used on construction equipment, trailers, antiques, bicycles, boats and numerous types of vehicles.

RFID chips can also be used in conjunction with a computer as part of an intelligent asset protection system to enable you to limit their use to a building or part of a building or even a larger geographical area.  The idea behind this is to stop people walking out of the office with equipment that should not be removed from the building.  As the chipped item of property passes a detection device an alarm is sounded and the matter then investigated.  Similar systems are used to prevent shoplifting and I‘m sure you have experienced the embarrassment of setting one of these alarms off when the retail assistant has forgotten to remove the device.