Liam Fox forecasts new threat to vital services

Liam Fox said the UK government was working with businesses and space experts to "build collective resilience" against the threat.

Dr Fox's comments at a conference in London on infrastructure security follows the United States space agency, Nasa, predicting a new wave of solar activity would peak in about three years' time.

He said: "Much of our critical national infrastructure depends on data and services delivered from, or through satellites, whose sensitive electronics are vulnerable to some of the radiation emitted by the Sun.

"Satellite operators recognise the effects of space weather, and the aviation industry has long been aware of the risk of exposing passengers to harmful levels of radiation at high altitude during severe solar events.

"However, effects on terrestrial infrastructure may be less obvious to service providers, such as the disruption to power networks, transport, telephone lines and essential services to our homes, businesses and government offices."

Dr Fox said the government would help efforts to improve the forecasting of such "space weather" and develop protective measures.

He said: "We are bringing together industry, academics, government and regulators in a collaborative approach to build collective resilience."

The Defence Secretary also warned that rogue states could detonate nuclear weapons in space to hit electricity and communications networks with a similar electro-magnetic pulse.

Solar flares are caused by explosions in the Sun's magnetic field, whose energy takes several days to reach Earth, 93 million miles away.

Current mitigation measures include disconnecting power lines or cutting transmission levels, moving high-flying military aircraft to lower altitudes and astronauts to safe areas. However, predicting their scale and timing is very difficult.

Professor John Brown, the Astronomer Royal for Scotland, said: "Dr Fox's summary of the advice he has received is essentially correct.

"The risk of it happening is small, and probably far less than the risk of rogue attacks, most likely on software like power grid controls than by the vastly more difficult nuclear explosion in space.

"However, a solar incident could happen and be much more widespread, and there is no doubt our communications, food chains and medical care are fragile as well as sophisticated."

However, Eric Priest, the Gregory professor of mathematics at St Andrews University, predicted the next peak in solar activity would be lower than average.

Liam Fox forecasts new threat to vital services - solar flares