We’ve already been one of the fastest countries in the world at decarbonisation.
You're right, and that's happened because we've had that cross-party consensus. This is why it's also right to criticise Badenoch for abandoning it. Progress isn't inevitable! If we suddenly reopen a bunch of coal mines, the fact (and as you say it is a fact) that we were previously really good on decarbonisation won't mean much.
But we could (and, given our history, should) be leaders. Even from a selfish perspective, there will be a huge demand for green technologies in the future, and we should be positioning ourselves to provide them.
We have SO much potential for wind, wave, and (given our expertise) small scale nuclear. Particularly windy and wave with the North Sea, Irish Sea, and the Atlantic.
Nationalise North Sea oil and gas production in collaboration with Norway. Jointly use the profits from the sale to exclusively invest in new offshore wind farms and wave farms, build energy islands to house the substation equipment and triple the number of grid interconnects to the EU to create a robust super-grid.
This then creates an international energy market where the UK national producer can sell excess energy to the EU countries.
Invest into clean hydrogen research for storage, transportation, and usage. Particularly in aviation and automotive.
Use some of the profits from nationalised oil and gas to offer incentives to companies that make inverters, generators, switchgear, and all the other components for power generation to build production facilities in deprived areas in the North of England, Wales, and Scotland to replace the jobs lost in oil and gas, with retraining expenses covered. Offer x-prises for rare-earth-free motors / generators and innovations in battery technology.
If the UK did that we'd have a HUGE trade portfolio in a market that is ONLY going to increase year on year for the foreseeable future that can be exported across the world and sold to rapidly expanding countries looking to move away from fossil fuels or countries that are looking to leapfrog fossil fuels like they did with leapfrogging landlines and going straight to cellular technology.
Britannia rules the waves? No! Britannia HARVESTS the waves!
A lot of that carbon has been exported to china of course; it wouldn't look so rosy if the carbon released to make all the imported stuff we buy was priced in.