|The Grimsvotn volcano began erupting on Saturday, sending thick plumes of ash into the sky [Reuters]
Several flights to and from Scotland have been cancelled after an ash cloud started heading towards the UK following the eruption of Icleand's most active volcano.
Dutch airline operator KLM, part of Air France-KLM, has cancelled 16 flights scheduled to fly to and from four British cities due to ash from the Grimsvotn volcano, KLM said on Monday.
The flights to and from Aberdeen, Glasgow, Edinburgh and Newcastle would be cancelled on Tuesday morning, KLM said in a statement.
British Airways (BA) said it was canceling all Tuesday morning flights between London and Scotland, one year after an eruption from another Icelandic volcano wreaked havoc on global aviation.
BA said that it made the decision to cancel all its flights until Tuesday 1400 (1300GMT) as a precautionary measure.
Scottish airlines Loganair and Eastern Airways have also cancelled dozens of flights.
The plume from the Grimsvotn volcano has already disrupted airspace over Greenland.
The ash cloud was also expected to reach Scandinavia on Tuesday, the Finnish Meteorological Institute said, and Finland's southern coast on Wednesday.
However a spokeswoman for the European Union said the ash cloud was "far from where we were a year ago", when the Eyjafjallajokull volcano caused the planet's biggest airspace shut down since World War II, with more than 10,000 flights cancelled.
A spokesman for Britain's Met Office said they expected winds to continue from northwest until about lunchtime on Tuesday, but weather conditions, including rain, were predicted to help.
"All sorts of things point to a relatively [optimistic outlook] I suppose in terms of what's happening with the weather patterns and the pressure unlike last year," he said.
The Grimsvotn volcano began erupting late on Saturday, and on Monday rose to between eight and 12 km, according to Eurocontrol, the Brussels-based body that co-ordinates air traffic.
Teitur Arason, an Icelandic meteorological office forecaster, said current wind conditions were spreading the ashes in separate directions.
"The winds high in the air, above 25,000 feet or thereabout, are southeasterly, so that ash is blown to the north and then later to the east," he said.
"But at lower levels, the winds are northerly and therefore those ashes are blowing southward."
Barack Obama, the US president, who is visiting Ireland, will leave the country for Britain on Monday night, a day ahead of schedule, because of fears over volcanic ash, a White House official said.
"Due to a recent change in the trajectory in the plume of volcanic ash, Air Force One will depart Ireland for London tonight. The schedule for tomorrow will proceed as planned," the official said.
The CAA said that since last year's crisis it had brought in new measures, including that areas of high, medium and low density ash will be identified using data from the Met Office.