Never mind the cost, it has taken the UK over a decade from initial decision to not yet completing Hinkley Point C. Nuclear is really slow to build. You can get a solid decade of carbon-free electricity out of solar panels in that time.

Panels today. Batteries as available. Nuclear eventually - maybe.

(people will respond with "what about SMRs", to which I will ask "what's the shortest time from decision to online that a SMR project has achieved?")