As someone who has come to believe in nuclear power as a vital part of a carbon-free energy mix, it gives me no pleasure to say this, but I don’t think Sizewell C will be built in the next 30 years, writes Paul Geater.

Last week’s decision by the British government to have another look at the deal to build a new power station at Hinkley Point in Somerset was a major shift in energy policy.

I don’t see this as a temporary halt so far as Sizewell is concerned. I think it will herald a major change in the UK nuclear policy.

It smells to me like the government U-turn of the early 1990s which left Sizewell B as the only new generation nuclear plant in the country after cost increases forced ministers to pull the plug on other reactors.

This time there is also the question of allowing Chinese involvement in the British nuclear industry – a prospect that clearly worries the new prime minister and her advisors.

I suspect that Hinkley will go ahead, rather like Sizewell B did in 1994, because £2.5bn has already been committed to the project. But that will be it for the foreseeable future.

I cannot imagine that Mrs May’s government will be happy to follow up George Osborne’s offer that the Chinese could build a new power plant at Bradwell – and I cannot see anyone else bankrolling an expensive new Sizewell C station.

One aspect of the cost of this scheme does puzzle me. The new power stations planned for Hinkley and ultimately Sizewell are totally new designs that have not yet been built anywhere in the world.

The costs, therefore, are essentially unknown.

Back in the early 1990s there was a plan for Sizewell C which was essentially a twin-reactor version of Sizewell B.

Now given that Sizewell B has been operating safely and efficiently for the last 22 years, why didn’t EDF just dust off that plan with a few updates?

They know the principle works. They know it could be putting a significant amount of electricity into the national grid within the next seven years, and their existing workforce already know the principle of its operation.

If the country does not build new nuclear stations, we are really facing difficult decisions in the mid 2020s.

I’m all for renewables. I actually like the look of onshore wind turbines and would like to see more wind farms both on land and at sea. There’s also a good case for more solar plants.

But the fact is that these are weather dependent electricity generation – and you need something that will still create power on cold, dark winter days.

And without nuclear, you are left relying on the fossil-fuel power stations polluting the atmosphere. However clean the gas stations are, that’s not really an attractive option for a world that is looking for energy sources that do not pump more carbon dioxide into the atmosphere.