I worked with CGI and CGI-Federal some years ago. Remember these are the same jokers who were the prime contractors on the US Healthcare.gov website that was a huge fiasco and had to be redone after failing spectacularly.
Like so many of the companies that specialize in government contracting around the world, they won contracts that they had no ability to deliver and then would contract to us for advice and delivering the difficult parts of what they had already promised the government (in this case Canada) they could deliver.
We charged them above our normal rate for this work and I am certain they marked that up substantially in the final accounting.
I now work with similar companies in the US and they do the same - win the contracts because of insider knowledge and dodgy promises and then go out to find subcontractors to deliver the actual work. I expect that the British taxpayers will be being fleeced by these sharks for years to come.