Hawker Hurricane MkIIc LF363 was buit in January 1944, believed to be the last Hurricane delivered to the RAF, and it was in continual service with the RAF until it crashed in September 1991 making it the longest serving aircraft in the RAF.
Ah, but was this operational service or partly as a display aircraft? I can't imagine any air force in the world still using the Hurricane as a front line fighter in 1991. This all depends on what you regard as 'operational' & 'continuous service' & whether a trainer like the Chipmunk is considered an operational type. The only model of Canberra now in RAF service is the PR9 as according to the MoD website the last remaining T4 was retired on 1 September 2005.
Both are somewhat different to the B2 that first entered service in May 1951 & the first PR9 was not delivered until 1959.
Sorry if this appears pedantic but the criteria for this sort of thing are very often not too clear.