"I'm sure Sir Humphrey would have meddled "
Which is one of those particular places where bureaucrats need to NOT meddle (except for safety regulators). Especially given the UK civil service's track record of backing "winners" and bankrupting private companies along the way (Beeching, Satellites, Brabazon, British Leyland, Every operating nuke plant being a unique design instead of a standard pattern, etc)
We need somewhere between 20-30 nuke plants _right now_ to replace existing power generation capacity (eliminating carbon) and include a safety margin for shutdowns plus another 30-60 to cater to eliminating gas/oil-fired central heating systems and an increased electric vehicle fleet.
I'd prefer they were LFTR but that technology isn't ready yet, which means "conventional" nukes until they are, then feed the waste into LFTR when it's ready. The absolute _LAST_ thing needed is a multiplicity of designs.
If Toshiba are laying the long game then more power to their elbow, but I suspect that noo-clea-are polyticks will get in the way.
Biting the hand that feeds IT
