Dont forget - in spite of the recent increased popularity of the armed forces in the public's eyes, there are NO votes in defence.
Have you ever heard a politician of any colour berating the other side for excessive spending and saying how many soldiers/helicopters/aircraft carriers that money could have bought? The only politically acceptable comparison in these circumstances is teachers/schools/nurses/hospitals.
I think it was Bliar who introduced the mantra - "health - education - health - education" and it has been enthusiastically taken up by the other side. Thus the number of pointless universities and inappropriately educated and unemployable "graduates" we have produced in recent years are the mirror image of the defence assets and service personnal we have lost in the same period!