The Ash cloud has grounded flights in Scotland, with BA, KLM, Aer Lingus and Easyjet among airlines suspending services in and out of its airports.

Drifting ash from an Icelandic volcano has caused severe disruption, including delays and cancellations following severe storms which have also affected road and rail travel across Scotland.

The volcanic ash is expected to reach London’s Heathrow airport – the world’s busiest international air travel hub – around lunchtime on Tuesday, Europe’s air traffic control organisation said.

Airport managers in Glasgow, Edinburgh and Aberdeen have said the situation is very fluid and urged passengers to contact their airlines.

Airports had been warned the ash plume would have covered the central belt by early morning, but ash is still only drifting across the north of the country.

Air traffic control organisation Nats said an area of volcanic ash is forecast to affect parts of Scotland until 1300 BST.

A number of airlines are choosing not to fly through Scottish airspace today:

British Airways is not operating any flights between London and Scotland until 1400 BST

KLM cancelled flights to and from Aberdeen, Glasgow, Edinburgh, and Newcastle as well as flights from Durham Tees Valley Airport

EasyJet cancelled flights to and from Edinburgh, Glasgow, Inverness and Aberdeen between 0500 and 1300 BST

Ryanair said it has been advised by the Irish Aviation Authority not to operate flights from Glasgow Prestwick, Edinburgh or Aberdeen until at least 1300 BST but believed that “there is no basis for these flight cancellations”

Flybe cancelled flights to and from Aberdeen and Inverness

BMI said flights to and from Aberdeen were subject to delay and passengers should check its website, but services in and out of Glasgow and Edinburgh were running normally

Glasgow-based Loganair has cancelled 36 flights. Only inter-island routes in Orkney are unaffected

Eastern Airways will not be operating any services in or out of Scottish airspace

Glasgow Airport advised all customers to check with their airline for updates. Aberdeen Airport said: “The high density ash is now overhead, and expected to remain in place for much of the day.”

Edinburgh Airport said that although the high density ash would not be overhead until later in the day, flights were still being disrupted. Red Cross volunteers have been helping about 400 passengers stranded in Edinburgh overnight.

Ryanair has objected to an order from Irish officials to ground its morning flights to and from Edinburgh, Glasgow and Aberdeen on safety grounds.

The company said it would complain about the “unnecessary cancellations” to the Irish Aviation Authority.

The cancellations come just over a year after another volcanic eruption in Iceland caused widespread disruption across Europe, including the closure of UK airspace, amid concerns about the damage volcanic ash could cause to engine aircraft.

This year, in the UK, the decision on whether to fly or not in ash cloud conditions is down to individual airlines, although they have to apply to the Civil Aviation Authority (CAA) for final approval.

Since last year, the CAA has graded ash levels as low, medium or high, and airlines are notified if levels reach medium or high

A CAA spokesman said the current cloud could “potentially” cause serious disruption as charts showed that the ash density below 35,000ft had reached the highest level at more than 4,000 microgrammes per cubic metre.

But he said procedures were “totally different” compared with last year.

He added: “If an airline has done a risk assessment as to how it will fly safely in medium or high ash levels, and has liaised with aircraft manufacturers and engine makers, then they will be able to fly if the CAA considers it acceptable.

“No UK airline has applied to fly in high-density ash, but a number have applied for, and been given, permission for flying in medium ash.”

US President Barack Obama, on an official visit to the UK, left Ireland for England Monday, a day earlier than planned, to make sure the ash cloud would not affect his flight plan

“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,” White House official John Earnest said.

The Grimsvotn volcano under the Vatnajokull glacier erupted Saturday, according to the Icelandic Meteorological Office.It is Iceland’s most frequently active volcano, and its last eruption was in 2004.