Fit key-operated window locks to all downstairs windows, those which can't be seen from the street, and easily accessible upstairs windows. For example those above a flat roof or by a drainpipe.

Even small windows such as skylights or bathroom fanlights need locks - a thief can get through any gap larger than the human head.

Remember to remove keys from locked windows and to keep them out of sight in a safe place.

Louvre windows are especially vulnerable because the slats can be removed easily from the frame. Glue the slats in place with epoxy resin, and fit a special louvre lock. Better still replace them with fixed glass.

If you are replacing windows - consider laminated glass. This glass has a layer of vinyl between two sheets of glass making it difficult to break.

As a last resort, consider fitting security grilles to vulnerable windows - many DIY shops now sell decorative wrought iron grilles.

If you are having new windows fitted make sure they are constructed to the recognised British Standard. BS7950/7412. This standard ensures that your windows are designed with security in mind. Ask your window company if their products comply.