The RAF, for example until recently had the job of patrolling our sea lanes using the best aircraft in the world for that task. Now, due to the ongoing assault on the armed forces by the present political clique, the RAF is unable to do that job.
What caused cancellation of MRA4 is well known. The political input was the decision to upgrade Nimrod in the first place, but they were poorly advised by those in MoD who knew it was compromised from day 1.
The decision not to replace this capability, which is a different argument, must lie at the feet of both politicians and VSOs. The former will, quite rightly, be mightily pissed off at £5Bn being poured down the drain after MoD (and in particular RAF VSOs) made a point of first deepening and widening the drain. The latter say nothing, because the truth exposes their feeble leadership and poor decisions.