Airlines warned of further ash chaos

Fresh plume from Eyjafjallajokull volcano will close airspace over Scotland and Northern Ireland

Air passengers face further disruption after the Civil Aviation Authority tonight said that airspace over Scotland and Northern Ireland will be closed from 7am tomorrow due to volcanic ash drifting south from the Eyjafjallajokull volcano in Iceland.

The cloud is expected to disperse by the afternoon and pose no further threat to UK airspace, but airlines urged passengers to check airline websites before going to catch flights.

The Irish aviation watchdog warned of a "summer of uncertainty", with sporadic disruption from the volcano's activity, despite introduction of a more nuanced safety code that will allow flights through ash-contaminated air.

Despite the relaxed restrictions, parts of the latest volcanic cloud were considered "too dense" under guidelines drawn up after consultations with engine manufacturers.

"We could be faced with this periodically [in] the summer," said Eamon Brennan, chief executive of the Irish Aviation Authority. "We are probably facing a summer of uncertainty due to this ash cloud."

Ireland and Northern Ireland reopened airspace this afternoon after a six-hour shutdown saw hundreds of services cancelled and added stress to David Cameron's dash to an Ulster Unionist party rally in County Down. Flights to and from airports in the Western Isles were also grounded for a while.

In continental Europe flights were not hit by the latest plume, except for those bound for Ireland, because of the new flight rules that let planes fly through low-density clouds of ash.

One victim was Ireland's transport minister, Noel Dempsey, who was unable to get to a meeting of his EU counterparts in Brussels. The meeting backed a proposal to unify European airspace by splitting it into nine blocks by 2012, but some ministers opposed awarding state aid to airlines to compensate the industry's loss of about £1.5bn last month when European airspace was shut for six days.

Andrew Adonis, the transport secretary, said: "The meeting agreed new measures to strengthen co-ordination between European aviation safety regulators, in the face of the continuing threat from the volcanic ash cloud. It was also agreed to support the continuation of EU regulations which require airlines to provide accommodation and assistance to stranded passengers."

A 24-hour general strike in Greece, called for tomorrow, to protest against austerity measures, forced easyJet and British Airways to cancel flights.