In the late '60s RAF aircraft were routinely operating far out over the North Sea, bringing the risk of pilots being forced to ditch, there was a need for an aircraft capable of carrying out search duties at long range. With the existing Nimrod fleet already heavily comitted elsewhere, proposals from various manufacturers were solicited. Due to limited budget, price was a major factor in the selection, so rather than opt for newly built aircraft the eventual choice was for ex-USAF B-66 bombers, refitted with TF34 engines ( two of which can be shut down in flight to save fuel ).

Italeri B-66 kit, with engines from a couple of S-3 Vikings