Plans to lift the UK flight ban were thrown into doubt this morning as a new volcanic ash cloud drifted towards Britain.
Some flights have taken off from Scotland, where airspace was reopened at 7am after air traffic control company Nats lifted restrictions. But there were only a handful of domestic flights, mainly to the islands, and the first international flight due to leave Glasgow has been cancelled.
Nats warned that the "situation was worsening" in some areas, but it said that other airspace could be available over England from 1pm although not as far south as London's main airports.
In a statement it said: "The volcano eruption in Iceland has strengthened and a new ash cloud is spreading south and east towards the UK.
"This demonstrates the dynamic and rapidly changing conditions in which we are working."
British Airways has cancelled all short-haul flights on Tuesday but said it hoped to run long-haul flights scheduled to depart after 4pm, depending on a "full and permanent" opening of airspace.