A major incident has been declared after an explosion was heard at a British power station just after 5pm.
It has been reported locally that at least one person has died in the blast.
Police, ambulance and fire services were called to the Didcot Power Station in Oxfordshire this afternoon, and reports have said that there have been a number of casualties.
The Oxford Mail was told by the South Central Ambulance Service that it has dispatched an air ambulance, three road ambulances, a rapid response vehicle and a hazardous area response team to the station.
The energy site houses six cooling towers, split between two stations, Didcot B and Didcot A.
Didcot B is currently an active natural gas power plant, and Didcot A was a combined coal and oil power plant before it was shut down in March 2013.
It is not yet known at which of the two stations the explosion took place.
A spokesman for energy firm RWE which operates the station has confirmed to an NBC reporter that there were no planned demolitions at the site today.
Rodney Rose, deputy leader of Oxfordshire County Council, told the Oxford Mail: “I have been told there has been one fatality, but the rest is currently unknown.
“The fire service is there now and we are still trying to find out if this was a demolition.”
Mr Rose, who sits on a committee responsible for Thames Valley Fire Service, added: “At the moment this is being treated as a collapsed building, not an explosion, but there was a bang.”
Pictures from the scene showed a significant chunk of a building in the defunct Didcot A site has collapsed, with a large amount of debris on the ground.
There is also a heavy emergency services presence.
It comes 16 months since a major fire struck a cooling tower at Didcot B in October 2014.
David Cooke, whose company Thames Cryogenics have a building overlooking the power station, said: “Our building shook and as we looked out of the window, the end of the main turbine hall collapsed in a huge pile of dust.
“It totally obscured the towers and must have drifted across the roads and main rail line. What’s left looks a tangled mess.
“The dust was hanging over the area for five to 10 minutes.
“First thought was, it didn’t looked planned, followed by the thought that people are going to have been hurt.”
Eyewitness Bill McKinnon, who lives in Didcot near the scene of the explosion, told the BBC: “I was sitting in my front room, I can see the power station quite clearly from where I am, it’s only about 400 yards away.
“About 4 o’clock, when I heard the explosion and the very loud rumbling, by the time I had got up and looked out of the window there was a huge cloud of dust which came through and over our village.
“When that had cleared I noticed that half of the old power station, where they used to keep the generators, half of that was missing.
“There wasn’t any physical feeling, it was only noise. When they took down the cooling towers a couple of years ago it was about the same volume as that. It was quite loud.”
He added: “I was a little bit surprised because normally the contractors let us know when they are going to do explosions, so I was a bit surprised because we hadn’t heard anything.
“Very shortly afterwards the air ambulance turned up and then fire engines and ambulances started arriving, and a little while after that another air ambulance turned up, and I think they are still there.”
Mr McKinnon said the explosion took place in a large building which housed the generators for producing power.