The original Network Rail plan had the entire London-Swansea section as priority project. Adonis's version broke the project into two phases, London-Bristol and Bristol-Swansea. The Coalition government modification was to extend the first phase to Cardiff and forget about a second phase. I guess some idiot thought that they can pretend to do more than the previous government on the cheap, and Swansea can then be reached with hybrid trains. Now they are effectively restoring a two-phase implementation, because the works for the London-Cardiff section were contracted already.

_{*Lunatic*, n.
One whose delusions are out of fashion.}