As Ash Cloud Advances the British Airports are getting Affected

Europe's busiest airport was set to close early Monday morning as a dense crowd of volcanic ash drifts across England from Iceland, aviation authorities said.

The airspace over London's Heathrow Airport will be closed at 1 a.m. Monday (0000 GMT; 7 p.m. EDT), Britain's National Air Traffic Service said in a statement late Sunday night.

The restrictions affecting Heathrow — as well as Gatwick, Stansted, and London City airports - will be in place until at least 7 a.m. Monday, the aviation authority said.

Airports across Britain and Ireland were closed for much of Sunday because of the drifting ash. The shifting of the no-fly zone southward will allow airports in northern England — including the key cities of Manchester and Liverpool — to reopen after 1 a.m.

In Ireland, Dublin's international airport closed early Sunday evening until at least 12 p.m. Monday (1100 GMT, 7 a.m. EDT). Some airports in Ireland's west were closed and will reopen at different times Monday, but Shannon and southern Cork were open "until further notice."

German authorities sent up two test flights Sunday to measure the ash cloud, one from the German Aerospace Center (DLR) and the other from Lufthansa, the country's biggest airline.

The DLR plane flew to southern England then continued north, collecting data from between 10,000 to 23,000 feet (3,000 to 7,000 meters). The Lufthansa Airbus A340-600, equipped with special scientific gear, left Frankfurt to fly over northern Germany, the United Kingdom and parts of Scandinavia.

All the data from both flights was immediately sent to aviation authorities in the U.K, the Netherlands and Germany, said aerospace center spokesman Andreas Schuetz.

In southern Iceland, activity at the volcano fluctuated Sunday but did not get more intense, civil protection official Agust Gunnar Gylfason said. He blamed the closures on shifting winds.

"What really changes the situation is the weather pattern," he said.

The Icelandic weather service said "presently there are no indications that the eruption is about to end."

"The closing of Manchester airspace once again is beyond a joke," Branson said in a statement. He said test flights have "shown no evidence that airlines could not continue to fly completely safely."

British Airways, facing cabin crew strikes beginning Tuesday, said it had canceled a small number of flights out of Manchester. The airline's chief executive, Willie Walsh, is to meet with British Transport Secretary Philip Hammond on Monday.

Eurostar, which runs trains between Britain and continental Europe, said it was adding four extra trains — an additional 3,500 seats — between London and Paris on Monday.