History of the Metropolitan Police Service by the end of the 19th century. During the 1860s, the flintlock pistols that had been purchased in 1829 were decommissioned from service, being superseded by 622 Beaumont–Adams revolvers firing the .450 cartridge which were loaned from the army stores at the Tower of London following the Clerkenwell bombing. In 1883, a ballot was carried out to gather information on officers' views on whether they wished to be armed, and 4,430 out of 6,325 officers serving on outer divisions requested to be issued with revolvers. The now obsolete Adams revolver was returned to stores for emergencies, and the Bulldog 'Metropolitan
National Identification Service National Identification Service The National Identification Service (NIS; also called SO4 from its Specialist Operations designation) is a department of the London Metropolitan Police which provides a range of support services on behalf of the Metropolitan Police and other police forces. All SO4's services are connected with criminal records and include a remit to act as the National Identification Service (NIS). The Metropolitan Police has had a national role in keeping criminal records since the 18th century but it was not until 1913 that the Criminal Record Office was established at New Scotland Yard. The NIS had sole responsibility for