All domestic flights across the UK have been cancelled as a volcanic ash cloud sweeps across the country.
The Met office advised the Air Traffic Control Service (Nats) to lockdown UK airspace as debris from an Icelandic volcano presented a serious risk to aircraft.
Every UK airport has been affected.
The volcanic ash is known to hamper a pilot's visibility, but more significantly it can damage aircraft engines.
Passengers are being advised to contact their airline before travelling to the airport.
A BAA spokesman said: "Passengers intending to fly today are asked to contact their airline for further information and should expect disruption in the coming hours."
The dispution is likely to spread to Europe later today.
A Nats spokesman said: "The Volcanic Ash Advisory Centre has issued a forecast that the ash cloud from the volcanic eruption in Iceland will track over Europe tonight.
"Nats is working with Eurocontrol and our colleagues in Europe's other air navigation service providers to take the appropriate action to ensure safety in accordance with international aviation policy."