New Scientist magazine has claimed that a terrorist attack on the Sellafield nuclear complex in northern England could potentially be 44 times worse than the Chernobyl disaster in 1986.
The magazine said that if a hijacked jumbo jet crashed into the part of Sellafield where radioactive waste is stored, as much as half the waste would be ejected into the atmosphere.
Sellafield has 21 concrete and steel storage tanks containing more than 1,500 cubic metres of high-level caesium-137 waste. That is around 90 times the level of waste released when the nuclear reactor at Chernobyl exploded 15 years ago.
New Scientist claims a jumbo jet crash would break open the Sellafield storage tanks and release a plume of radioactivity into the air.
The burning fuel would also continue to pump radioactive material into the atmosphere, while a collapse in the cooling system would cause surviving storage tanks to heat up and spew out more radioactivity within hours.
The magazine said an incident like this "would contaminate large parts of Britain and, depending on which way the wind was blowing, Ireland, continental Europe and beyond. Some places would become inhabitable."
Following the Chernobyl disaster in Ukraine in 1986, an exclusion zone of 4,800 square kilometres was established around the plant.
Radiation spread so far that sheep in some parts of Wales still have to be tested before they are allowed into the food chain.
So far, the disaster has caused 11,000 confirmed cases of thyroid cancer in Ukraine and Belarus.