This is painted in the 'Raspberry Ripple' colourscheme, usually seen on test aircraft operated by the research and evaluation sections of the UK Ministry of Defence.

This information supplied by Dick Clements:
The Red White and Blue Colour scheme is that of the special Trials and Test department of the UK Ministry of Defence (MoD). This operation is run as part of the test and evaluation activity of the Procurement and Evaluation Group known as MoD(PE). They have title to lots of aircraft that are at places such as DERA (Defence Evaluation Research Agency), AAEE (Aircraft and Armaments Evaluation Establishment, RAE (Royal Aircraft Establishment) etc. A wide variety of aircraft have flown with these groups, nearly all by either RAF aircrew or specialist employees of specific manufacturers. The RAF and RN don't get anything unless it's been passed by these boys for release to service. In addition these groups do all the flying research for the military and development flying of experimental types. AAEE also houses the ETPS (Empire Test Pilots School).
More of:
This event (Air Tattoo 1999)
This aircraft type (canberra)

Image #72