© APActivity from the Eyjafjallajökull volcano has increased, taking the ash plume to a height over 30,000ft
Air chaos from volcanic ash may return within days because of wind direction changes, weather forecasters and aviation chiefs warned last night.

The warning came just hours after all UK and Irish airspace re-opened yesterday following two days of disruption centred on Scotland, Ireland and the North of England.

It also came as the Icelandic volcano at the heart of the problem yesterday increased the amount of ash it is belching out.

The UK's Met Office said the wind was blowing the ash to the South West and out to sea and this was likely to continue into the weekend.

But it warned last night: 'As we move into next week there's the chance that it could turn back to blow from the North West and bring more ash over the UK.

'It's something we are keeping an eye on. We are in the hands of mother nature.'

The boss of Britain's Civil Aviation Authority has also warned that volcanic ash will continue to disrupt passengers on UK flights 'for the foreseeable future' - despite the re-opening of the skies.

The Irish Aviation Authority (IAA) also warned: 'If the winds change the larger concentrated ash cloud could be blown over Ireland, UK and Europe.

'This will result in traffic restrictions.

'Passengers planning to travel by air over the coming days are advised to regularly check with their airlines and the IAA website in advance of going to the airport.'

The UK's Met Office said in a bulletin: 'Information received from the Icelandic Meteorological Office confirmed that activity from the Eyjafjallajökull volcano increased taking the ash plume to a height over 30,000 ft.

© PAPassengers at Glasgow Airport yesterday wait for buses to take them to other airports after flights were cancelled due to the ash
'The ash cloud remains to the west of the British Isles today and with winds likely to remain from the north-east into the weekend, the risk of the ash cloud affecting UK airspace in the next couple of days remains low.'

But a spokesman added: 'That could change if the wind changes.It's also dependent on the concentration of ash. We are monitoring constantly.'

Experts have warned that the erupts could last for months, or even a year

CAA chief executive Andrew Haines warned air passengers: 'Ash is likely to continue to disrupt UK air travel for the foreseeable future and our advice to passengers is to listen to updates and contact their airline before leaving home if they are concerned their travel plans may be affected.'

National Air Traffic Services (Nats) said all airports across the UK reopened at 7am. Airports in the Republic of Ireland reopened at 4am.

A statement from Nats said: 'The no-fly zone imposed by the Civil Aviation Authority tracking the high density area of the volcanic ash cloud has moved west overnight and has now cleared UK airspace.'

Passengers seemed uncertain as to which airports were operating flights, a problem highlighted by Scotland's First Minister Alex Salmond, who accused the CAA of releasing a 'vague' statement.

Last month hundreds of thousands of Britons were stranded abroad and faced long delays when European airspace was closed from April 15 to 20 after the eruption of the Eyjafjallajokull volcano, leading to the cancellation of 100,000 flights affecting 10 million passengers across Europe.

Travel insurers say they are likely to pay out £62 million. The cost to airlines is about £2million. BA says it cost up to £20million a day.