The cause of the problem is a denehole, an underground gap left by chalk excavation in 17th Century.

BBC: Hole in Blackshots Lane, Grays, prompts evacuation

The shortages are made worse, it said, by excavation work that has severed underground power lines 70 times this year.

WSJ: Social Media

After this, excavation work can start to lay the foundations of the nuclear plant including two underground 3km tunnels for the cooling water.

BBC: New nuclear power plant at Hinkley Point C is approved