Spewing ash from the erupting Eyjafjallajokull volcano in Iceland grounded much of European air traffic for nearly a week in mid-April.

Airlines had to cancel around 100,000 flights, stranding millions of passengers.

Since then the ash has periodically forced short-term closure of parts of airspace in countries across Europe, including Spain, Portugal, Ireland and Germany.

Philip Hammand, the British transport minister, said on Saturday that five-day rather than the previous 18-hour ash prediction charts would be made available to airlines and the public on the Met Office forecaster's website.