I am sure the Treasury had a large say in the decision. In the 1980s, when the Bucaneers began to show signs of wing spar problems, most of the fleet was fixed.

Not entirely – a number that were too far gone were taken out of service and scrapped, some newer examples were OK without any work, I think the rest had an spar mod programme. Part of the reason the spar failures had happened was, in addition to the switch from low-level over sea to land, the effects of the wingtip extensions added on the S2. Many (but not all – Thunder City Buccs still have S2 wingtips) Buccs reverted to the shorter S1 wingtip to reduce stress.

Probably the main reason the Bucc fleet was patched up rather than being phased out was that the RAF needed them. There was no replacement or fallback available unlike with the Valiant where there were two, newer, better alternatives in service.