INSURANCE company Norwich Union has launched a flood map to help the owners of 5,000 properties.

The company said its digital map of the York area was the largest and most accurate ever undertaken in Britain, and could pinpoint the risk of river flooding to individual properties.

This means homeowners could now receive more accurate premiums than with the traditional postcode system.

As well as showing if a property is at risk, the map also shows how often a flood is likely to occur and what depth the waters are likely to reach during incidents

The map was drawn up using an aeroplane which criss-crossed the country for nine months, recording radar images to produce a digital model showing the height of the ground above sea level.

Jill Boulton, Norwich Union's geographic information systems manager, said: "The ability to pinpoint whether an individual house is on a hill or raised ground, and how floodwaters will flow, is invaluable in the fight against flood damage.

"The new information will help to convey to customers from around York just how severe the flooding risk to their property will be and how often a flood can be expected."