While one or two people have mentioned ongoing safety issues, I think the scenario you describe - making a decision to go/no go with extra funding while risks and uncertainties remain - is one that has cropped up before on this programme. In such circumstances, it is a brave man (sometimes in the Yes Minister sense) who decides to pull the plug.
As a former CDP once said "Cancellation is sometimes good". Of course, many of his staffs promptly interpreted that as "cancel at the first sign of a minor risk", which explains a few capability gaps I can think of, and resultant fatalities. A generation and more in DPA / DE&S have been brought up on that ethos. It makes you wonder how many are left who know how to identify, manage and mitigate minor risks, never mind serious ones. I know some very senior people in DE&S who remain convinced "Risk Management" means opening up a risk register, inserting a few minor issues and then close it and walk away; never to be opened again. In fact, that was the way our Nimrod 2k/RMPA/MRA4 2 Star insisted risk was managed.
With todays announcement of BAeS job losses, there will be many hoping a public inquiry follows.