Britain's airports were deserted this evening after an unprecedented airspace lockdown sparked by a deadly cloud of ash from an Icelandic volcano.
With no flights in or out of the UK until at least 7am tomorrow, millions of passengers now face a weekend of chaos.
Individual airlines have made the decision to cancel their flights for even longer - British Airways has grounded its flights until 9am tomorrow, while Ryanair and Flybe routes have been cancelled until at least 1pm tomorrow.
More than 500,000 passengers a day fly in and out of Britain on around 5,300 flights. Experts say the disruption - which is already spreading across Europe - could last for days.
The Met Office said volcanic ash will cover the UK until 12pm tomorrow.
Cancellations will have a particularly disruptive effect on families returning from the Easter holidays who were due to fly back to Britain this weekend.
And the closures will have more effect on British travellers than the chaos after the September 11 terror attacks. Although American skies were closed for two days, British airspace remained open.
Experts say the ash could take between 24 and 36 hours to drift across the UK if there is no volcanic activity.
But tonight Einar Kjartansson, a geophysicist at the Icelandic Meteorological Office, said: 'It is likely that the production of ash will continue at a comparable level for some days or weeks.
'But where it disrupts travel, that depends on the weather. It depends how the wind carries the ash.'
By mid-afternoon airports across Britain were already deserted. Heathrow was eerily quiet - much to the delight of residents living nearby.
While having some sympathy for those stranded by the move, they described having clear skies as 'bliss'.
Television and radio presenter Richard Madeley, who also lives under a flightpath, wrote on Twitter: 'Flipside tho is no noise in the sky at all, and no con trails. We under Atlantic flights path and it's eerily quiet today. 19thC quiet!'
Phillip Schofield wrote on the site: 'Eerie sight looking at the sky over London and not seeing a single plane. Funny how you miss 'em.'
A spokesman for Britain's Civil Avation Authority described the airport closure as 'unprecedented' and that the fall-out could go on for days - with the knock on effect adding to the turmoil.
'It all depends which way the wind blows - literally - and whether there is another volcanic eruption,' said CAA spokesman Richard Taylor.
He added: 'It's absolutely unprecedented. We can't think of any incident of volcanic ash which has affected UK airspace in this way.
'It is worse than the 9-11 terror attack. That stopped transatlantic air traffic. But even then, flights to the Continent and within the UK continued.'
Tonight, a group of scientists were due to embark on a 'very dangerous' mission, flying up to the volcanic ash cloud to take samples from the plume.
On board a specially-designed plane, they will gather data which could reveal important information about the environmental impact of the eruption.
The group, which set off from Oxford Airport this afternoon, includes two emissions scientists and two instrument operators, flown by a pilot and co-pilot.
The mission's objective is to determine the plume's speed and direction and the findings of the four to five-hour operation will be passed on to the Met Office.
Peter Purcell, of the Natural Environment Research Council, based at Gloucester Airport, said: 'I don't believe that anybody has really used an aircraft to sample the edge of these plumes before - it is actually very dangerous.
'If you fly into the ash and your engines stop, you crash.'
But he said their plane - a Dornier 228 - was equipped with instruments which will warn pilots how close they are to the volcanic cloud.
'We can then fly at a level which is not a level of danger,' he said.
Business Secretary Lord Mandelson defended the move to ground all flights today.
'Nobody in business or indeed the travelling public will welcome the decision to close down UK airspace,' he said.
'But the safety of people has to come first. That comes above every other consideration.
'It's inconvenient but when you have a volcanic dust cloud coming over the UK in this way we have got to protect the travelling public.'
Air traffic controllers were forced to shut British airspace after the eruption of the Eyjafjallajokull volcano in Iceland yesterday spewed massive clouds of ash thousands of feet into the sky.
It is the second time the volcano has erupted in a month. But the second explosion was ten to 20 times more powerful than the one on March 20. Eyjafjallajokull had previously been silent for almost 200 years.
Scottish passengers were the first to feel the impact of the eruption as Aberdeen, Glasgow and Edinburgh airports were closed this morning.
Christine Campbell, 55, was at Glasgow Airport to fly to La Rochelle, in France, for her son's wedding.
She said: 'When we arrived we were told there were no flights going out today and to go home. But I wanted to come and wait anyway because I didn't want to miss anything.
'I'm really disappointed and upset because I've been looking forward to this wedding for two years and at the last minute there's this hiccup.'
She was planning to try to get a train to London and then travel to France by Eurostar.
Ann Cochrane, 58, a market researcher originally from Beith in Ayrshire, was trying to get home to Toronto where she now lives.
She said: 'I think I might cry. I just wish I was on a beach in Mexico. We took a cab at 7.30am this morning and they told us about what was going on and said we should go home.
'It's not so bad for us because we're only down the road so we will just hire a car for another day, but other people live hours away.'
A critically ill patient had to be flown from Scotland to London by military helicopter - the only aircraft suitable to make the journey.
The woman was taken by ambulance from hospital in Dunfermline, Fife, to HMS Gannet at Prestwick.
From there a Royal Navy Sea King helicopter flew her to London, landing in Regent's Park at around 9am. An ambulance then took her to University College Hospital.
Tonight the Ministry of Defence ordered all flights - not just the RAF but also the Army and Navy - to be cancelled.
The only aircraft getting off the ground were the search and rescue helicopters operated by the RAF and Navy who were told that in an emergency they could fly.
But elsewhere all Britain's defence airfields were closed down until further notice and the skies were clear of military jets.
It was the same 'no fly' rule at the U.S. airbases across the UK.
The grounding meant that three squadrons of F15 strike aircraft - like those used on operations in Afghanistan and Iraq - had to stay in their hangars and all vital refuelling, transport and reconnaissance flights were cancelled until further notice.
Matt Dobson, a forecaster for MeteoGroup, said ash would come down in Scotland, Denmark and Norway and could continue to affect airspace until tomorrow.
It cannot be seen from the ground as it blowing across Britain around three miles in the sky.
Ash can disrupt the engines of an aircraft and reduce visibility as well as affecting landing and navigation gear.
However, the substance does have one plus - for most people it will just mean a spectacular red sunset.
Air travellers hit by the grounding of all flights by the volcanic ash threat can still claim most of their EU rights even though the disruption is beyond airlines' control, the European Commission confirmed tonight.
Travel operators remain liable to reimburse ticket fares or to re-route their stranded passengers - but will not have to pay financial compensation for delays or cancellations, because of the special circumstances.
P&O Ferries reported a surge in passenger numbers following the airports' shutdown, while Channel Tunnel high-speed train company Eurostar said it was carrying increasing numbers on its London to Paris and Brussels services.
Some passengers unable to fly on domestic routes switched to rail, with train companies putting on more services on the East Coast and West Coast main line routes.
National Express laid on extra coaches.
Scores of tourists and around 800 residents had to be evacuated from their homes last night after the volcano erupted.
Rivers rose by up to ten feet (three metres) as the ferocious temperatures melted the glacier, turning it to water, which gushed down the mountainside.
Iceland's main coastal ring road was closed near the volcano, and workers smashed three holes in the highway in a bid to give the rushing water a clear route to the coast and prevent bridges from being swept away.
Iceland, a nation of 320,000 people, sits on a large volcanic hot spot in the Atlantic's mid-oceanic ridge. Volcanic eruptions are often triggered by seismic activity when the Earth's plates move and when magma from deep underground pushes its way to the surface.
The last time there was an eruption near the 100-square-mile (160 square-kilometre) Eyjafjallajokull glacier was in 1821.
STRANDED - BUT STOICAL - TRAVELLERS
At HEATHROW, Bill Burrows, 90, and friend Linda McIntyre, 70, feared the delays because of the volcanic ash had put paid to their dream cruise around the Caribbean.
The pair had travelled up from their homes in Worthing, West Sussex, to Heathrow, by taxi. Unfortunately for them their taxi had already left by the time they realised the situation.
Mr Burrows said: 'We were going to catch a flight to Miami then on to Costa Rica and catch the cruise there. We're supposed to be spending tonight at the Hilton in San Juan, before we join the ship - the Celebrity Cruises Millennium - and sail to Cartagena, in Colombia.'
The 14-night trip, which they had been looking forward to since the end of last year, cost them £1,700 pounds each.
'We checked the internet this morning and it said everything was okay,' Mr Burrows added. 'It wasn't until we got here that we realised it was cancelled.
'The Icelanders took all our money and this is what we get in return - ash,' he joked.
Passengers were less stoical at GATWICK where they claimed there had been little information about when they would get away.
Heather Smith, 63, retired, from Portadown, Northern Ireland, was trying to get to Belfast on her way home from a Greek holiday.
She said: 'There really has been no information. Nobody knows what's going on. They say I should go home and look online, but I don't live here, and I don't have any access to the internet. What am I meant to do?'
At MANCHESTER, construction students Lee Dinsdale, 20, Rob Ellams, 22, and Fraser Morson, 21, were heading back to Tameside, Greater Manchester, after their £420 week-long package holiday with Jet2 was scrapped.
Mr Dinsdale, of Ashton-Under-Lyne, said: 'All my savings have gone into this trip and we've been told it's an act of God, so there is no refund. We wanted to be in Sharm El Shiekh not Stalybridge.'
Russell Craig, Manchester Airport spokesman, said: 'This is unprecedented. I have worked here for seven years and I have never seen a situation like this. At least if it is snow people can see it. The sky however appears to be clear.'
EDINBURGH was one of the first airports to close.
Gultekin Gurdal from Izmir, Turkey, was set to fly home after a business meeting in the Scottish capital.
The 41-year-old librarian said: 'My taxi driver told me that all flights were cancelled but I didn't believe it.
'Then I came to the airport and the airline told me "yes, all flights are cancelled". It's unbelievable, just unbelievable.'
HEROIC AIRLINE CAPTAIN WHO SAVED 263 PASSENGERS AFTER FLYING THROUGH VOLCANIC ASH STORM
Captain Eric Moody was the airline captain who saved his crew and 263 passengers after flying into a cloud of volcanic ash.
He was commanding a London to Auckland British Airways Boeing 747 in June 1982, when it flew into an ash plume from the erupting Mount Galunggung in Java, Indonesia.
At first Captain Moody, co-pilot Roger Greaves and senior engineer officer Barry Townley-Freeman were unaware of exactly what had happened.
A strange St Elmo's Fire-like light had appeared on the cockpit windscreen and sulphur-smelling smoke started filling the passenger cabin. Within minutes, all four engines had failed.
The plane rapidly fell from 36,000ft to 12,000ft but the drop caused the ash to solidify and break off which cleared three of the engines and allowed the crew to restart them.
Despite severely limited vision and a host of other landing problems, the crew managed to get the plane safely down at Jakarta airport.
It was later discovered that as the ash cloud was dry it did not show up on the weather radar designed to detect the moisture in clouds. The crew received various awards for their heroic efforts.
Speaking today, Captain Moody told Sky News that the experience had been terrifying.
'All the engines stopped for 14 to 15 minutes and we didn't know what was happening,' he said.
'We glided the aircraft about 80 nautical miles and went down 37,000ft to about 12,000ft. That was when we must have come out of the bottom of the ash cloud. It was a dark old night.
'Flying into volcanic ash is as deadly as flying with ice on your aircraft. And everyone knows how dangerous that is.'
Source : dailymail