It can be hard to tell whether a car is stolen. Its identity may have been changed. For example, the identity number and number plate of a legitimate car may be transferred to a stolen one. Vehicle registration documents can be forged or obtained by fraud. But there are tell-tale signs to look out for. Ask to see the vehicle registration document (V5). If the seller can't produce this document, be suspicious. A common excuse is that it has been sent to the DVLA (Driver and Vehicle Licensing Agency) for updating. This may be true, for example, the seller may have changed address recently. But be wary. It means you cannot check the car's ownership and identity details.

The seller should have a green slip if the car was bought very recently and the V5 is with the DVLA for the change of ownership to be recorded. This applies only to cars that have been issued with new V5s, introduced in March 1997.

Are there any spelling mistakes or alterations to the V5? If so, it may be a forgery. All legitimate V5s have watermarks.

Ask for proof of identity and address such as a driving licence, passport, recent gas or electricity bill. Check that the same name and address is given on the V5.

• the vehicle registration mark (the number plate);
• the vehicle identification number (VIN) - this can be found on a metal VIN plate, usually in the engine compartment, and stamped into the bodywork under the bonnet and the driver's seat. As a security measure some cars have the VIN etched on their windows or lamps;
• the engine number.

Have the identification numbers been tampered with? The engine and VIN numbers may have been interfered with. Areas of glass may have been scratched off the windows, or stickers may cover up etching which has been altered.

Another clue is whether the seller can show you the insurance policy for the car. If it is stolen, probably not.

Use the checklist to help you spot the signs of a stolen car