There is still widespread disruption to 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

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

And there have been reports of heated scenes at airports across Europe, with "fists flying" in Palma as exasperated tourists struggle to return home.

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

A spokesperson for the airport said: "Schedules continue to be affected by yesterday's restrictions on UK airspace.

"While the majority of passengers will still be able to travel, there will unfortunately be some disruption on some routes, including flight cancellations.

"It is important for all passengers to check the status of their flight with their airline before travelling to Heathrow."

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

British Airways appears to be the worst affected airline.

Elsewhere, London Gatwick said it plans to operate a normal schedule on Tuesday following the disruption.

However, passengers have been advised to check the status of their flight with their airline before travelling to the airport.

London Stansted also said it planned to run a normal flight schedule on Tuesday, but added "our terminal may be busier than anticipated".

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.

Major UK airlines such as TUI and BA warned of "significant delays" for passengers amid changes to schedules, with airports urging travellers to check with their flight operators before they head to the terminal, in case of delays and changes.