Check to see who it is by using the spyhole if you have one, or look through a front window. Always put the chain on before you open the door. (If you don't have a chain it's a good idea to get one - they don't cost much).

With PVC doors, it can be difficult and costly to fit a door chain. Check with the manufacturer before you buy a PVC door, that a chain can be fitted.

Fire safety - only put on your door chain as you answer the door - don't keep it on all the time as this could delay your exit in the case of fire.

When you open the door:

• Look at their clothing. Some official callers will have a uniform bearing their organisation's name or symbol.
• If you don't know the caller, ask to see their identity card. Check it carefully, and keep the chain on while you do this. Genuine callers won't mind if you close the door while you do this.
• Some public utility services (eg water, electricity, gas) operate a password system. Contact your utility provider - their number will be on your bill.
• If you are still not sure, ask the caller to come back later. You can then check their story by phoning the organisation or company they claim to represent. Look up the telephone number in your own directory. Don't rely on their card - it may be the number of a crook's partner.
• Bogus callers usually work in pairs. Beware of one distracting you while the other steals your property. The best practice is not to let them in.
• Watch out for anyone who says they are in a hurry. Don't let them pressure you. If in doubt, call a neighbour or friend.
• If you have any suspicions at all, don't let them in.

If you are still not happy, phone the police - dial 999 - and tell them what's happened. And tell your neighbours.