Widespread disruption continues at UK airports after the incident on Bank Holiday Monday, which meant flight plans had to be uploaded to systems manually, slowing or cancelling air traffic across the country.

Mark Harper stressed that technical experts have ruled out a cybersecurity incident, with the Civil Aviation Authority (CAA) set to investigate.

"Something on this scale hasn't happened for almost a decade - normally the system works very well," Mr Harper told Sky News.

Britons sleeping on floors in airports - live updates

Some 790 departures and 785 arrivals at UK airports were cancelled on Monday, according to aviation analytics firm Cirium - around 27% of all scheduled flights in and out of the country.

Thousands of passengers were affected by yesterday's disruption - with aviation analysts warning there could be knock-on effects for days to come.

Prime Minister Rishi Sunak said Mr Harper would remind airlines about their responsibilities to passengers hit by air traffic control disruption, telling reporters: "I know people will be enormously frustrated by the disruption that's impacting them.

Mr Sunak added: "The transport secretary is in constant dialogue with all the industry participants, he will be talking to airlines specifically later today and making sure that they support passengers to get home as quickly as possible."

An investigation into what happened on Monday will be carried out by National Air Traffic Services (NATS) the Civil Aviation Authority said, which added passengers can look at its website to see what help they are entitled to.

Flights are running - but there are warnings of cancellations and delays

There have been reports of heated scenes at airports across Europe, with "fists flying" in Palma as exasperated tourists struggle to return home, while others sleep out in airports in the hope of catching a new flight.

Heathrow Airport says services will remain disrupted today - and passengers are being urged to contact their airline before heading to the terminal.

More than 60 flights have been cancelled at the west London airport - made up of at least 32 departures and 31 arrivals.

Elsewhere, London Gatwick said it plans to operate a normal schedule on Tuesday following the disruption, though at least 23 departures and 51 arrivals were listed as cancelled at the airport.

Outside of London, Glasgow said a handful of flights will be disrupted as a result of Monday's issue, while departure boards at Manchester and Bristol airports show a small number of services have been cancelled.

'I don't like the ending to this story'

Travellers from the UK have reported disruption both in the UK and abroad - with some saying they may not be able to fly until the weekend.

TV host Ore Oduba posted on Instagram saying his cancelled easyJet flight from Greece left them "stranded" with no supplies for their two toddlers, mocking the voucher they had been offered from the airline.

Meanwhile, athletes and broadcasters who have been out at the World Athletics Championships in Budapest, Hungary, have also reported delays, with sport presenter Jeanette Kwakye writing on X, formerly known as Twitter: "No idea when I'll be back, any suggestions for ways home that don't involve 36 hours of travelling or endangering my life are welcome."

She added: "I don't like the ending to this story."