HINKLEY Point C will cost up to £2.9 billion more than anticipated and could go on line 15 months later than planned, EDF Energy has admitted.

A detailed review of costs and schedules has revealed that the construction bill for the giant project had climbed by between £1.9b and £2.9b from the company’s last estimates.

This would increase the total cost from £19.5b to between £21.5b and £22.5b.

It is already eight years behind schedule and, although EDF hopes that the station will be completed by the target date of 2025, the risk of its being delayed to 2026 has increased.

But local MP Ian Liddell-Grainger said he still believed the station would be generating power on time.

“EDF has kept me fully informed about the financial over-run,” he said. He was confident the company was facing the latest challenges “in a robust way”.

In a statement, EDF said: “Cost increases reflect challenging ground conditions which made earthworks more expensive than anticipated.

“Revised action plan targets and extra costs were needed to implement the completed functional design which has been adapted for a first-of-a-kind application in the UK.”

EDF said the extra costs would be funded by the company and its Chinese partner CGN with no impact on UK taxpayers or consumers.

In a letter to staff, the company said: “Getting this far has cost more money than we anticipated. Our earthworks are complete but challenging ground conditions meant we overspent to finish them on time.”

EDF strategy director Paul Spence said: “We’ve given the best view we can, given what we know. I can’t say today what will happen over the course of the construction.”

Mr Liddell-Grainger told the Free Press: “Remember it is EDF and its backers, not us the taxpayers, who carry the risks in this case.

“EDF has invested heavily and devoted almost two decades to planning this project. It remains the biggest infrastructure build in Europe. It is not gong to stop. EDF is here to stay.

“I will be keeping a very close watch on developments and staying in regular touch with key Ministers.”