If you had relatives who served in London’s Metropolitan Police Service this is a useful site. The records started on the formation of the Metropolitan Police in 1829 with well over 500,000 entries up until 1945. These records do not include the City of London Police or British Transport police.
What the database does hold are records of officers joining or leaving the force, transfers, death or pensioned from service and the issue of medals from the Metropolitan Police. You can also see the Divisions with names of the police stations as well as a chronological list of all the Police Commissioners and Home Secretaries from 1829 to the present.
There is also a useful photo section showing the epaulettes showing the badges of rank (useful if researching photographs of police uniforms)
This is an ideal source of information for the genealogist/family historian who had family members who served in the Metropolitan Police Force. These records can be sourced at the National Archives.
Mike
Family Tree Folk
http://www.familytreefolk.co.uk/