It's the reverse. Green electricity is held back from adoption because the price is linked to the price of gas. While ever that link exists, electricity will be unnaturally expensive in comparison to its raw market price.
It's not completely irrational, although arguable (I would be on this point of view for instance) it's now out of date. The idea is to pick the most expensive bid price for the spot market price, not the cheapest, in order to incentivise continued operation of difficult energy sources. Why would you want to? Because in ye olden days 'difficult' were things like the hydro power or nuclear which were great for maintaining base line load and which you wanted to subsidise to keep going.
In today's market, that's completely on its head and renewables are the cheapest. Established nuclear second, granted construction costs of new nuclear make that overall cost higher of course. This is why the government is incentivising pushes towards heat pumps etc. - the more we get off gas, the less reason to maintain this market oddity exists and it can be removed making electricity cheaper again.
This is easier said than done. Much of the UK's housing stock would need improvement before heat pumps are viable. I recently had a survey on my own house for instance, and it came back as non-viable without a lot of improvements around heat loss first. These improvements would be a good thing and are semi-subsidised, but it's still effort. I believe the new build rules have finally, years late but finally, been changed to require standards around heat pumps and solar.
So yep - electricity being expensive in the UK is not due to the renewables or nuclear, it's due to gas. And the reason we still rely on gas so much is inertia plus building standards and upgrades. Hard one to unpick, but got to start somewhere.