> The deal took over a decade and not only includes upfront costs but also British bill payers giving a "generous" subsidy to French energy for 35 years.
Not so. The deal is only to guarantee the price of electricity sold, which had to be done to remove financial uncertainty over decades in order for EDF/Chinese partner to agree to finance it.
[0] https://en.wikipedia.org/wiki/Cost_of_electricity_by_source#...
If the strike price used were the current market rate (or maybe a bit lower), that would seem reasonable to allow a company to have the required long term security knowing the bottom won't fall out from under them, but an implicit subsidy does not seem like a good strategy.
That's just a direct consequence of the government policy of not financing the construction and operation with public money.
The alternative was to directly spend public money, which makes the complaint about this guaranteed price being a public subsidy rather moot.