Let me put this another way. This can be looked at as a problem with at least seven dimensions that vary geographically (actually way more but let's try these):

History
Imperial power
Electricity consumption
Marginal costs of buying precursors of methods of energy production
Capital costs of methods of energy production
Marginal costs of methods of energy production
System costs of methods of energy production

Let's first assume for the sake of it that the UK stays a country, and retains the same geography. I've ordered the dimensions roughly according to their decisiveness in the situation.

Consider the UK's situation:

The UK is not determining world history.
The UK's imperial power has ended and that of its long term great power ally is evidently in decline.
The UK's per capita energy consumption is declining and this is good.
Currently out of the UK's control for oil or gas, not very meaningful for renewables or nuclear
Very high for nuclear, high for gas but already established, lowest for renewables
Very low for nuclear and renewables, very high if you need to conduct new drilling for gas
High for renewables (higher storage and grid costs), lower for nuclear (safety), lowest for gas

A rational reflection on this situation is found in the UK's "clean power" target for 80% wind and solar generation, 5% fossil and 15% "other" (nuclear, biomass, imports) etc by 2030.

Now here's my read on what you're saying:

History isn't happening!
The UK must be very powerful!
—
The UK must be able to conduct wars 5,000 km away because it will always need to control global oil and gas reserves because its energy prices will always be sensitive to that control!
The UK already has gas so it is the cheapest unless of course the UK ever needs more energy than the installed base, to replace infrastructure, to meet its commitments on climate change or to have energy prices that aren't sensitive to wars 5,000 km away!
The UK should pursue the method of energy production with the highest and most volatile marginal costs and definitely should never have energy prices that aren't sensitive to wars 5,000 km away!
The system costs mean renewables should never happen even thought the total costs of production and system are still much lower for renewables!

If you think this is unfair, just tell me where it is, I'm quite honestly wide open. Evidently these aren't the only factors but at least it's a systematic way to look at the situation. If you want to add problem dimensions or dispute the determinations and values, just go for it.

We seem to be headed for a weird scenario where you only re-orient your view on the energy base when the UK's already running 85% on solar and wind and more than half the country's driving shiny Chinese EVs.