London airspace has been closed until further notice, following an air traffic control computer failure.
The computer failure, at the National Air Traffic Services control centre in Swanwick, Hampshire, was announced at around 3.30pm this afternoon.
All flights in and out of London were expected to be grounded until at least 7pm, causing a massive backlog of delays and potentially cancellations.
Thousands of travellers were facing long waits at Heathrow, Gatwick, Stansted and London City airports.
If you are among them you have rights entitling you to help and assistance from the airlines while you wait for your flights. These entitle you to food, drink and if the delays carried on overnight, a hotel stay.
Know your rights: My flight has been delayed, what can I claim? – see our consumer rights guide
Flight delay rights
Travellers also have the right to compensation for cancellations and certain delays. However these do not apply if the problem is caused by anything classed as ‘extraordinary circumstances’.
Airlines are highly likely to argue that Friday’s power outage was such an extraordinary circumstance and will resist paying any compensation
Know your rights: My flight has been cancelled, what can I claim? – see our consumer rights guide
Which? executive director, Richard Lloyd, said: “The Denied Boarding Regulations provide a means for consumers to claim compensation for delays and cancellations however if an airline is able to demonstrate the cancellation or delay was due to extraordinary circumstances then they don’t have to pay out.
“Passengers may however still be entitled to refreshments, free phone calls and overnight accommodation depending on how long the delay is, how far you are flying and whether the flight is to or from an EU or non-EU airport or on an EU or non-EU carrier.”