How will the energy be provided?
We have no coal-mines, yet Drax, Retcliffe, Fiddlers and Ferrybridge still need feeding.
Many of our nuclear plants are at the end of their lives. Replacements take years to build.
Fusion is still way in the future.
What do we do in 25 years or so when all the nice fracking gas runs out?
Renewables.....Wind and solar......Great, but, - how do you deal with a month-long blocking anticylone.......In the winter......At night?
'Peak Oil'.....When supplies start to decline, how will the moving-parts of HS2/3 etc be lubricated?