London yesterday became the first major UK city to provide crime data to the public in the form of an online mapping service.

The initiative, launched by Mayor Boris Johnson, provides a colour-coded guide to crime in particular areas in a format similar to Google Maps.

The service specifies rates of particular types of crime - burglaries, robberies and vehicle offences - and provides data down to sub-ward level.

"Crime-mapping puts information in the hands of every London citizen," said Johnson.

"This is a major step forward in enabling Londoners to assess the work of their local police in tackling the crimes that affect their neighbourhood."

The system is based on a widely used service in the US.

Public surveys have proved the maps to be popular, according to the Metropolitan Police.

"There has been a growing and understandable appetite for people to know more about what crime is happening in their local areas," said deputy commissioner Sir Paul Stephenson.

The Information Commissioner's Office has backed the maps, although it warned the Met against providing data which shows the specific location of offences as that would infringe the Data Protection Act.

Westminster has the highest rate of crime per population, according to the map, while Harrow and Richmond-upon-Thames have the lowest.

The service is available at the Metropolitan Police Crime Mapping web site.