Flagship carrier British Airways says it has suspend flights between London and Scotland as a cloud of ash from an Icelandic volcano drifts towards Britain.
"Following forecasts of significant volcanic ash in Scottish airspace, (we) have decided as a precaution that it will not operate any flights between London and Scotland on Tuesday ... that
arrive in Scotland before 2pm (2300 Monday AEST) or depart from Scotland before 2pm," a BA statement said.
"At present all other flights are unaffected," it added.
OBAMA DELAYED
Travel plans were thrown into disarray for hundreds of passengers while even US president Barack Obama was forced to amend his itinerary, flying into London earlier than planned to avoid the dense plume drifting towards the UK.
Forecasters predicted the volcanic cloud, which billowed from Iceland's Grimsvotn volcano, would hit Scotland and Northern Ireland in the coming hours, with much of the country being covered by Tuesday.
But as a string of carriers announced cancellations, Transport Secretary Philip Hammond said Britons "have got to learn" to live with chaos caused by volcanic activity in Iceland.
"My understanding is that we have gone through an unusually quiet period for volcanic eruptions in Iceland over the last 20-odd years and we are moving into a period when there is likely to be significantly more volcanic activity," he told BBC2's Newsnight last night.
"So this is clearly something we have got to learn to plan around. We have got to learn to live with it."
But he insisted there were now "much more robust systems" to "minimise the disruptive effect".
Since last year's eruption, the authorities have gained a "much better understanding" of the risk from ash clouds and are able to assess the thickness of different patches as well as the possibility of flying over or below a cloud, he said.
"Most importantly, the basic situation now is that the threshold for most aircraft is 20 times where it was last year. We have got from 200 micrograms per cubic metre to 4,000 micrograms per cubic metre as the threshold up to which most aircraft can fly.
"What we can't promise is that there won't be disruption when there is a major natural event like this."
However, he insisted the airlines were "making the decisions".
"They have looked at the projections for tomorrow and said `This is not something we can fly in'.
"If they wanted to make a safety case to fly in the conditions that are modelled for tomorrow, they would have to put forward a safety case to the CAA that would then consider it."
According to the CAA, all British aircraft can fly in medium density ash.
However, the Met Office charts show that the levels are higher than this below 35,000 feet, meaning planes could have to navigate routes around the plume.
A CAA spokesman said the cloud, as it is now, could "potentially" cause serious disruption.
"At this moment in time it is difficult to know what might happen," she added.
"If we have high density ash at low levels it may be that you can fly above it."
Met Office forecaster Charles Powell said the plume could hit parts of Scotland between 1am and 7am and large swathes of Britain by lunchtime.
"This area of ash will start to make its presence felt across parts of Scotland and Northern Ireland and by midday I think much of the UK will be covered," he said.
Responding to warnings, British Airways announced it would not operate any flights between London and Scotland before 2pm.
Only last year, the airline's then chief executive Willie Walsh criticised airport closures and said blanket bans imposed on flying were "a gross over-reaction to a very minor risk".
Dutch airline KLM said 16 flights scheduled to and from Glasgow, Edinburgh, Aberdeen, and Newcastle would be cancelled, while Eastern Airways, based in Kirmington, north Lincolnshire, axed all flights and easyJet grounded some planes.
While further disruption is expected later in the week, the Civil Aviation Authority (CAA) has stressed that the UK is in a much better position to deal with the problem than it was last year when Iceland's Eyjafjallajokull erupted, causing the closure of airspace and the cancellation of thousands of flights.
But the White House opted to take no chances ahead of the president's highly-anticipated state visit to Britain.
Mr Obama was due to arrive in London from Ireland on Tuesday but instead flew into Stansted on Air Force One on Monday night.
Football club Barcelona saw its travel plans thrown into disarray ahead of the Champions League final against Manchester United on Saturday. The Catalan club will wait for Tuesday's forecast before deciding when players will travel to London for the game.
