Airline passengers are facing massive disruption across the UK after an ash cloud from a volcanic eruption in Iceland grounded planes.
The Air Traffic Control Service (Nats) said no flights would be allowed in or out of UK airspace from midday to 1800BST amid fears of engine damage.
Airports operator BAA confirmed all flights at Heathrow, Stansted and Gatwick would be suspended from midday.
And in Scotland, authorities have already shut all their airports.
The restrictions, in accordance with international civil aviation policy, were imposed after the Met Office warned ash could clog engines.
Passengers were advised to contact their carriers prior to travel.
'Significant disruption'
Experts have warned that the tiny particles of rock, glass and sand contained in the ash cloud would be sufficient to jam aircraft engines.
Aberdeen, Edinburgh and Glasgow airports were shut as Nats said it was restricting flights "in accordance with international civil aviation policy".
The ash cloud disrupted all flights to and from Manchester with a similar picture at Newcastle airport where all arrivals were cancelled and all outbound flights either cancelled or subject to indefinite delay.
Liverpool's John Lennon airport suspended all flights until at least 1300BST.
http://news.bbc.co.uk/1/hi/uk/8621407.stm