Interesting gamble the government is taking here. Unusually the environmentalists are right to be cautious, SMRs have been designed since the 90s and not a one of them has ever come to anything.
Also not completely sure why we’d need it. By the governments own plans we can expect our wind power to jump from 10gw to 50gw by 2035, which would mean being 100% renewable powered for months at a time.
Which will make it very very expensive, the research I’ve seen recently says nations that manage that transition can expect electric price falls of a quarter to a half, and that Hinckley plant is already going to be selling at over twice the unit price of any other source. I would expect SMR plans to collapse for that reason by itself.
So on both points:
Recent studies have shown that the intermitency of wind and solar means countries with a high reliance on it are especially prone to gas price shocks, that issue dissapears if the country has a good amount of nuclear or hydroelectric in the mix.
Regarding geothermal the UK, particularly parts of Scotland, are actually rather suited to more modern types of geothermal with a lot of hot dense rock at depths we previously couldn’t drill too but are now much more able to.
There’s new geothermal being implemented in the southwest too for what it’s worth - so it’s not like it’s not happening in the UK, it’s just going to be at the extreme south and north.