Large solar flares were unleashed when energy stored in magnetic fields above sunspots was suddenly released, according to the scientists at Britain's Royal Astronomical Society.

The effects of the solar flares were seen at different points on earth, including brilliant auroras over parts of Britain on Friday night.

"Flares can affect short-wave communications and satellites in the earth's orbit, which could mean problems for phones, television and radio signals," Peter Bond, spokesman for the Royal Astronomical Society, said.

"The flares have caused a huge amount of geo-magnetic activity as the magnetic field takes a while to settle," he said.

It was the largest radiation storm since October 1989, according to experts.

The Earth's magnetic field was also bombarded with extra energy from the sun on 24 October 2003 when a geomagnetic storm sent charged particles that affected electric utilities, airline communications and satellite navigation systems.