An East Anglian locomotive for the first twelve years of service, 70013 Oliver Cromwell entered traffic on May 30, 1951, being allocated first to Norwich shed, then Ipswich from September 14, 1958, before reverting to Norwich on January 4, 1959. In September 1961, 70013 Oliver Cromwell moved to March but as dieselisation took hold on the BR network, the locomotive moved to the north-west, along with many of the other Standard Class 7 'Britannias'.
Allocated twice to Carlisle Kingmoor; in December 1963 and December 1966, Cromwell also spent time at Carlisle Upperby between February 1965 and December 1966. For the final year of BR mainline steam, 70013 Oliver Cromwell moved to Carnforth from January 9th and was withdrawn from service on August 17, 1968. The locomotive's final journey was to Norwich, via Doncaster, on August 12th, from where it was towed to Diss for transfer to Bressingham.