Officials in Britain and the United States are preparing to make controlled power cuts to their national electricity supplies in response to a warning of a possible powerful solar storm hitting the Earth.

Thomas Bogdan, director of the US Space Weather Prediction Centre, said that controlled power "outages" will protect the national electricity grids against damage which could take years to repair should a solar storm collide with the Earth without any precautions being taken.

Dr Bogdan is in discussions with scientists in the UK Met Office to set up a second space weather prediction centre in Britain to co-ordinate a global response to a threat viewed seriously by the US and UK governments.

One of the subjects is how to protect electricity grids from the immense power surges caused by the geomagnetic storms which happen when highly energetic solar particles collide with the Earth's magnetic field.