Ideally, the RAF would've had a medium-long range bomber, but it didn't because there were other priorities. The UK was hardly abundant with cash during much of the Cold War era, and there was strong political will in places to limit defence spending so as to spend scarce resource on schools, hospitals etc.
- Nuclear deterrent needs to be kept out of harms way. Keeping it on land invites its destruction by conventional means. This is of especial importance to nations like the UK and France who could give a superpower aggressor a very bloody nose, but not overwhelm them, so would definitely not want to be in the position of having to use their nuclear arsenal in the face of conventional attacks upon said arsenal. The safest place is aboard submarines. So, unless the UK government decided to get rid of its (strategic) nuclear weapons, it's not going to put them back aboard vulnerable aircraft at vulnerable airfields.
- The UK is within easy flying range of the European WW3 battlefield, so why spend precious funds on aircraft that are for 90% of likely missions redundant?
Better 400-odd Tornadoes, Buccs and Jaguars than a far smaller fleet of equally vulnerable bombers.
- Soviet air defences. Quite difficult to get past, or could be by the time your bomber force is developed. So why bother?
- The Sea Harrier and Harriers aboard 'aircraft carriers', friendly/allied airbases around the globe, would allow for extended operations.
As said, a nice bonus to the RAF, but hardly first-place on the shopping list.