Privatizing parts of the UK's foreign ministry was supposed to save money but cost money instead.

Privatizers typically claim that it will do the same job and cost less, for some theoretical reason such as "investment" or "improved methods" or "economy of scale". Over and over, the result is the opposite. Do they then respond, "It was worth trying, but it failed, so let's now unprivatize that"?

Never. Because those theoretical reasons are merely excuses.