A cloud of volcanic ash is heading for Sussex after a massive eruption in Iceland.

Gatwick has announced that flghts from the airport have been suspended on advice from forecasters - and this will now be in place until tomorrow at 7am at the earliest.

A statement on the airport's website said: "Following advice from the Met Office, the National Air Traffic Service (NATS) has introduced restrictions to UK airspace this morning as a result of volcanic ash drifting across the UK from Iceland.

"These measures currently affect Aberdeen, Edinburgh and Glasgow airports which are closed but may also affect other parts of the UK later today.

"Passengers intending to fly today are asked to contact their airline for further information and should expect disruption in the coming hours."

More than 300 flights from Gatwick have already been cancelled.

Gatwick has now advised passengers that there will be no further flights taking off or landing today.

A statement on the airport's website said: "Until at least 6pm there will be no flights in UK controlled airspace other than in emergency situations.

"It is likely that there will be continued disruption after 6pm and Friday morning.

"We strongly advise passengers not to travel to the airport, but to contact their airline for the latest information and for re-ticketing."

Air traffic control company National Air Traffic Services has announced that no non-emergency flights will be allowed in or out of the UK before 7am on Friday ''at the earliest''.

The cloud, from the Eyjafjallajokull volcano which errupted on Tuesday, is expected to spread over Sussex later today.

On this realtime map of flights over the UK, you can see how the cancellations are quickly spreading south.

However, for most people the cloud of volcanic ash drifting across the country will just mean a spectacular red sunset.

The cloud will not be noticeable from the ground and is not expected to affect the weather.

For air passengers that will be little consolation, with thousands grounded across the UK.

But Dr David Rothery, from the department of earth and environmental sciences at The Open University, said flight restrictions were an essential safety precaution.

He said: "The eruption of the Eyjafjallajokull volcano in southern Iceland, which climaxed yesterday with flooding and a tall eruption column driven by expanding steam, distributed fine rock particles known as 'volcanic ash' as high as 11km into the atmosphere.

"This ash cloud is now drifting with the high altitude winds.

"The main mass is over Scandinavia, but it is also over the north of Great Britain and is likely to spread south over the whole island by the end of the day.

"This is not a dense cloud, and is unlikely to be noticed by people on the ground, though we may have a spectacularly red sunset this evening.

"However, air traffic restrictions have very properly been applied, resulting in closure of airports and airspace.

"This is because if volcanic ash particles are ingested into a jet engine, they accumulate and clog the engines with molten glass."