Speculation is mounting that the Government is set to give the go ahead for the first new nuclear power station to be built in the UK for a generation, creating thousands of jobs.

A decision on the Hinkley Point C plant in Somerset could be made on Thursday, clearing the final hurdle in the delayed £18 billion project.

French energy giant EDF has already made its final investment decision on the scheme, but the Prime Minister stunned the industry by saying she wanted to review the details.

An announcement has been expected since the start of the week, but could now be made just before the Commons recess ahead of the political party conference season.

During her recent visit to the G20 summit in China, Theresa May defended the delay, insisting it was down to "the way I operate" because she wanted a fresh look at the evidence.

The go ahead will spark a fresh row about the high cost of energy from Hinkley, with EDF being paid £92.50 per megawatt hour of electricity generated.

A Chinese firm has a third stake in the scheme and is hoping to build other new nuclear power stations in the UK at Bradwell in Essex and Sizewell in Suffolk.

Justin Bowden, national officer of the GMB union, said: "Giving the thumbs up to Hinkley is vital to fill the growing hole in the UK's energy supply needs.

"It will be a big relief for the 25,000 quality jobs which were put at risk by the latest delay, never mind the reputational damage inflicted on UK plc.

"The GMB has always had reservations about linking Bradwell and Sizewell with the contract for Hinkley. The Government should never have allowed the country to be held over a Chinese barrel."

Earlier on Wednesday, a source at Downing Street dismissed reports Mrs May had made a final decision on Hinkley as speculation.

ITV News reported she had intended to make an announcement on Monday but had to postpone.

According to ITV, the PM was set to call French president Francois Hollande on Monday afternoon and then announce that the project was back on track.

But Business and Energy Secretary Greg Clark raised some last-minute concerns, forcing Mrs May to postpone the planned phone call and delay the announcement, according to the report.

Juliet Davenport, chief executive of independent renewable energy supplier Good Energy, said: "The decision to go ahead with Hinkley C is a bad move.

"It will take at least a decade to build and leave our grandchildren an inheritance of high energy costs, hazardous waste, security worries, and a plant that needs complex and costly decommissioning.

"No wonder only 36% of the British public support nuclear, compared to a whopping 76% for renewables.

"The same future generations that will blame us for Hinkley could instead thank us for a legacy of investment in renewables.

"The transition to renewables is inevitable and brimming with economic opportunity - the UK should embrace it."

Stop Hinkley campaigners will join Greenpeace to hand in a 300,000-name petition to 10 Downing Street on Thursday, calling on Theresa May to drop the "eye-wateringly expensive" Hinkley and invest in renewable power instead.

Stop Hinkley spokeswoman Sue Aubrey said: "There is no widespread support for new nuclear, particularly at Hinkley Point.

"Consumers can tell that the project may be unconstructable, requires vast subsidies and would generate electricity too expensive to use."

Greenpeace released a poll which it said showed public support for Hinkley was at an all-time low, with just a quarter of the 2,000 people surveyed saying they supported the project.

John Sauven, Greenpeace executive director said: "Support for Hinkley is at rock bottom.

"The public knows what the Government has yet to learn - investment in renewables should be prioritised over nuclear power.

"The Government shouldn't risk taxpayers' money on old-fashioned, flawed technology. It should be investing in the future.

"Advances in renewable energy like offshore wind, alongside battery storage, energy efficiency innovations and wires that carry electricity under the sea connecting us to other countries are the future for keeping the lights on.

"It is time the Government embraced these developments, rather than lock us into a contract that will leave future generations with more hazardous nuclear waste, higher bills and dependent on French and Chinese state-owned companies for our power."

The Prime Minister's official spokeswoman stressed that the deadline for a decision on Hinkley Point remained the end of September.

There had been speculation that any announcement would have to be made on Thursday this week, when the Commons rises for a recess lasting until October 10.

But the spokeswoman said: "We made very clear when we set out the timetable in July that it would be by the end of September. We did that knowing the parliamentary timetable."

Asked whether the decision has to be announced in the Commons, the spokeswoman said only that ministers will "keep Parliament updated on the decision moving forward".

She added: "There is no update on this. We have set out very clearly what is going on. We are committed to making a decision by the end of the month. That's the approach.

"We haven't taken the decision yet. The Prime Minister has not been in touch with the Chinese."

CND general secretary Kate Hudson said: "We urge Theresa May to put the interests of the country first when she makes the Hinkley decision.

"The basic facts have not changed: the nuclear power deal is hugely expensive - a £30 billion subsidy will be handed to the French state in addition to what consumers pay. It's dangerous: cancer clusters, nuclear accidents and disasters like Fukushima, and there is still no safe way to store nuclear waste.

"It amounts to burdening future generations with an environmental and social disaster that cannot be compensated for with the expensive electricity the plant will produce.

"Renewables offer a clear alternative. If Hinkley is scrapped, billions can be invested in the UK developing the technology we need to tackle climate change and secure a cheap and reliable energy supply."