BAe got paid a lot to do stuff, and have got to the point where BAe will have had most of the dosh for a failed system. You can't really blame BAe for that, nor the CS type who doubtless chaired the meetings - the RAF should have had competent engineers (and, dare I suggest, the odd aircrew type) onboard to ensure BAe stayed honest.
Having seen a project managed by a senior (ish) CS type, ably supported by a senior (ish) RAF officer or two, it used to completely do my head in to see various small parties take advantage of the setup to score themselves paltry gains whilst letting the contractor away with whatever they wanted. Put competent bums on seats, preferably slightly awkward ones who will ask awkward questions and insist on awkward standards being met, and rubbish like this wouldn#t happen in the first place.
FWIW Cameron is probably no worse than anyone else - he's trimming fat that doesn't exist, and personally I think there are many areas of fat still to be trimmed before defence, but he's no worse than any other politician. They're all scum, of course, but Cameron's no worse than the rest... I'd rather be a pimp than an MP!
Dave