Ed Merrison & Carole Erskine, Sky News Online

Air passengers could face further delays after warnings that a "new ash cloud" is spreading towards the UK.

Air traffic control company Nats said the "situation was worsening" in some areas.

But it said Scottish airports should be available from 7am and other airspace over England from 1pm, although not including the main London airports.

"The volcano eruption in Iceland has strengthened and a new ash cloud is spreading south and east towards the UK," Nats said in a statement.

"This demonstrates the dynamic and rapidly changing conditions in which we are working.

British Airways sent a test flight into the ash cloud

"Latest information from the Met Office shows that the situation is worsening in some areas.

"Based on this information, the situation for Northern Irish airports for the morning is uncertain, due to the new ash cloud.

"The latest information shows that Scottish airports should be available from 7am and more airspace over England may become available from 1pm, although not as far south as the main London airports."

Nats said it would provide further updates at around 3am and 7am.

Stranded passengers at JFK airport in New York