The RAF taking over the Strategic Nuclear Deterrent is well and fine. But look what happened to the RN after it got Polaris. Bye bye CVA01.
I would imagine in todays even tighter budgetary constraints should the RAF want to take over the deterrent role it will have to face some large cuts in other areas. Yes an airborne nuclear deterrent would be cheaper then submarine option but still some large cuts elsewhere will be required.
I wonder what the reaction of the Chief of Air Staff would be if he is told "Yes you can have the deterrent role but you have to bin eurofighter, Nimrod Mk4 and say four or five front line bases to fund it".