The Royal Navy SIB is the smallest of the three SIBs , with the SIO holding the rank of Lieutenant Commander . They investigate : all incidents falling within Schedule 2 of the Armed Forces Act 2006 ; Although an SIB appears to have existed in the British Army of the Rhine in Germany between 1919 and 1926 , the origins of the army 's SIB are in 1940 , when twenty Scotland Yard detectives were enlisted in the Corps of Military Police to deal with the pilfering of military stores within the British Expeditionary Force ( BEF ) in France . The unit was formed on the recommendations of Detective Chief Inspector George Hatherill ( who later went on to investigate the serial killers John Reginald Christie and John George Haigh , and the Great Train Robbery ) and command was given to Detective Superintendent Clarence Campion , head of Scotland Yard 's Criminal Record Office , who was commissioned as a Major . Campion was hit in the head by shrapnel during the Dunkirk evacuation and died on 20 May 1940 , the only SIB casualty of the BEF . After this beginning , the SIB was established on a full-time basis . One of the first group of detectives , Frank Elliott , was sent out to Cairo , Egypt . Under the supervision of Colonel Claude Harper , Elliott managed a 500-man force which investigated crime in Egypt , Palestine and later Libya
Great Train Robbery
Great Train Robbery (1963)
Special Investigation Branch