At the moment we may aswell sell the Typhoons, cut the Navy and get rid of Challenger tanks etc, whilst recruiting enough for 5 more commando units, double the army and buy all the A-10's available to support them oh and buy more helicopters that work in the environment.
That'll help with Afganistan, but we'll be screwed when someone decides that our little island would be better off speaking German or Mandarin.
And anyway the F-22 may well be bloody expensive but when you lose a jet, you also tend to lose the highly trained item of nose ballast. It doesn't matter how much it costs to train a pilot or navigator, but it does matter that no country can afford to lose a small and finite resource.
If that means that the pilot has a greater chance to return to base after shooting down more of the enemy then the F-15 doesn't seem to be quit such a bargain.