G4S deal

I notice that the £284 million new deal private security firm G4S struck with the (Tory) Government was, in effect, that they would get £20,000 per security employee, for each of the 13,700 security staff they promised to supply (but will fail to supply) for the Olympics. We all now know how little training and vetting those staff are getting.

But my question is - why was the deal ever made in the first place? G4S are paying those staff £6.50-£8.50 per hour (after promising £14 per hour, according to one potential employee.) Three weeks full-time work at 40 hrs per week will earn each security employee a maximum of about £1,000 each.

So, where does the other £19,000 go that we the British taxpayers are paying for each of them? How on earth could this have been thought a good deal for the British public?

I imagine G4S are generous Tory party donors but is there any other explanation?