Eurostar has announced that it will be adding extra trains to its schedule today because of the airline disruptions.

An additional service from London to Paris has been scheduled for 15:01 today, along with a return journey at 20:36. The company already added an extra train from Paris to London yesterday.

Eurostar has also asked passengers not to come to the very busy stations today unless they already have a ticket.

Disruption across UK airports is still widespread.

Analysis of flight data websites by the PA news agency shows at least 281 flights, that were both supposed to arrive and depart from the UK's six busiest airports, have been cancelled so far today.

Here is the breakdown by airport:

• 75 at Gatwick
• 74 at Heathrow
• 63 at Manchester
• 28 at Stansted
• 23 at Luton
• 18 at Edinburgh

Many other flights were significantly delayed and thousands of air passengers are still stranded.

Image source, Reuters

As things stand, there is no definite answer about the exact cause of all the disruption.

What we do know is a technical fault yesterday caused the automatic system for processing flights to not work, meaning things had to be handled manually - slowing down the process.

The knock-on effect could last for days, with backlogs being dealt with and other issues like planes being in the wrong places.

As we've been reporting, any speculation that the disruption may have come as a result of a cyber attack has been dismissed by the government.

Transport Secretary Mark Harper told the BBC earlier he was not rushing to conclusions, and the Civil Aviation Authority will do a report on the incident.

The UK based air traffic control service Nats said yesterday evening the issue had been remedied and it was working to establish exactly what happened.

A Downing Street spokesman has reiterated earlier comments from Transport Secretary Mark Harper that yesterday's air traffic control fault was not caused by a cyber attack.

He added that they would not speculate further on the cause.

“The information we have is that there was not a cyber attack. The exact cause of the technical incident will be subject to the investigation by the Civil Aviation Authority and then submitted to government," he said.

The past 24 hours have been confusing and frustrating for many stranded in airports in the UK and abroad. Here's what you need to know:

Why have flights been disrupted? More than a quarter of UK flights were cancelled yesterday after a technical issue hit the UK air traffic control system. Some airports are now returning to their normal schedules but thousands of passengers have been affected. The cause of the fault is not known yet.

How long will the disruption last? Transport Secretary Mark Harper says "it will take some days to get people back to where they should be". Those scheduled to fly tomorrow could still face "residual delays", travel expert Simon Calder explained.

What about compensation? Stranded air passengers scheduled to board flights covered under UK law have rights, and airlines must let passengers choose between a refund or an alternative flight - find out more about these options here.

Image source, Dan Mayberry

Dan Mayberry, 27, who travelled to Tenerife for nine nights with his girlfriend, was due to fly back to London yesterday and arrived at the airport at 17:00 local time.

"There have been babies put in suitcases as makeshift beds, people on the floor, people sleeping in wheelchairs. The airport themselves put out emergency beds and they weren’t announced to anyone, it was just if you were on that end of the airport," Dan tells the BBC.

After their flight was cancelled they were told to book an alternative flight via the EasyJet app but there were no flights to the UK before early next week.

Dan and his girlfriend ended up having to book flights to Paris to get home that way as they are both teachers and had to book their own flights. The cost for the new flight with accommodation will be £2,000.

EasyJet tells the BBC that availability on some direct flight routes is limited at this time and that they have been advising customers who make their own alternative travel arrangements that they will be reimbursed.

The airline is also looking at how it can offer additional seats by flying larger aircraft and operating additional flights to repatriate customers where alternative options are most limited.

Image source, Ryanair

About 40,000 Ryanair passengers had their flights cancelled yesterday, the airline's CEO has said.

Michael O'Leary said the airline expects to cancel about 70 of its roughly 3,200 flights today.

The airline cancelled about 250 flights yesterday, and about 20 aircraft had not been able to return to their home bases, he added.

O'Leary said he expected services to return to normal by tomorrow.

He said the airline had been in contact with Nats, which runs air traffic control in the UK.

"We haven’t had an explanation from them on what exactly caused this failure yesterday and where were their back up systems," he said.

Image source, Reuters

We're now hearing from Wizz Air, who says none of its flights have been cancelled today, but it is "likely that some moderate delays may still occur as the UK system gradually returns to normal".

In a statement, the airline it had to delay and cancel flights yesterday, adding it has "taken significant steps to try and limit the disruptions on Monday alone, and the situation seems to be progressively stabilising".

The Hungarian airline operates short-haul flights from UK airports including Birmingham, Edinburgh, Aberdeen, Gatwick, Luton, Liverpool and Bristol.

Image source, PA Media

The outlook remains grim for many travellers across the UK, including Northern Ireland.

Belfast International Airport, the largest in the region, said there will be "more delays and cancellations" today and advised travellers to check with their airlines for updates.

There has also been a knock-on disruption to the Irish system.

AirNav Ireland, which provides air traffic management services for Irish airspace, said it was working with airlines and airports to manage affected flights "as efficiently and quickly as possible".

Carmel McArdle was due to fly to Belfast from Stansted airport on Monday evening. She told BBC News NI she decided to travel by train to Liverpool and catch a ferry this morning,

"I couldn't get the information and honestly I was so flustered I decided to book onto the train and go for the ferry in Liverpool," she said.

Read more about the situation in Northern Ireland here.

Image source, nats

A former air traffic control manager has been shedding some light on the situation, what happened and just how uncommon these mishaps are.

Doug Maclean, from Ayr, told us the statement , externalfrom the National Air Traffic Service (Nats) was "very basic and very straightforward".

"There was a problem with the flight data processing system which captures all of the advance and forward information between air traffic control centres," he says.

"That was a major problem. It was going to run out of data in four hours so they had to manually input and they solved the problem in the middle of the afternoon yesterday.

"So far they haven't explained what the problem was. But, it is a fairly rare occurrence to have these things happen."

Thomas Mackintosh
Live reporter

I've been speaking to James Groot who is stuck on the Greek island of Rhodes.

EasyJet have cancelled his flight to Edinburgh and said the earliest flight they can get him on is in ten days.

He told me there has been confusion on the ground at Rhodes Airport and only one member of staff working at the EasyJet desk there who he described as "stressed".

"They say flights are on the app and then when you go through it says 'not available'. So we started to look ourselves. We found one alternative route Rhodes to Helsinki; Helsinki to Verona, Verona to Glasgow then a train to Edinburgh."

James and his family are staying in Rhodes hoping the situation sorts itself out quickly.

EasyJet said in a statement , externalyesterday: "The safety and wellbeing of our customers and crew is our highest priority and while these circumstances are outside of our control, we would like to apologise for the inconvenience caused and to reassure customers that we are doing everything possible to minimise the impact of the disruption."

London North Eastern Railway has announced it is offering free travel for people whose flights back to the UK were affected by the air traffic control chaos.

LNER said passengers having to land at a different airport, travel on a different date than originally planned, or needing to return home earlier could get free tickets today.

Passengers who want to take advantage of this will have to present a boarding pass or airline ticket.

Image source, EPA

If your flight has been disrupted, you'll want to know what your rights are.

Well, we've put together the best tips on whether you can get a refund or an alternative flight.

The tips also include what to do if you're stuck abroad and are entitled to food or accommodation and what to do if you booked a package holiday.

• You can read it all here in our simple guide

Erika Phillipson, a British citizen who lives in France, has been trying to fly to the UK from Nice since yesterday.

After a delay of more than eight hours at Nice airport, she received an email just before 23:00 local time from Jet2.com saying her flight had been cancelled.

“There were six flights cancelled much earlier, all of those given hotel rooms, and so we had to search around the local area to try and find a room at three o’clock this morning," Phillipson tells the BBC.

Phillipson, who has fused vertebrae in her neck and lower spine and says her back is “screaming in agony,” is heading back to Nice airport this morning to see if there is any possibility of travelling today.

“We’re going to go back to the airport and wait, and hope, and see if we can actually get some information," Phillipson says.

The BBC has contacted Jet2 for comment, who said : "Our teams have been in contact with Ms Phillipson as they continue to work hard to fly our customers home at the first available opportunity and can confirm that Ms Phillipson will be flying to the UK this afternoon."

Image source, Reuters

Prime Minister Rishi Sunak has been speaking to broadcasters this morning and acknowledges that passengers will be frustrated by the disruption to their travel plans.

Earlier, Transport Secretary Mark Harper told the BBC that the disruption will last for several days.

Sunak says Harper is in "constant dialogue" with all the industry participants and will be talking to airlines later today.

The PM adds that passengers have rights with regards to accommodation and alternative flights and Harper would be making sure airlines "honour those obligations".

Image source, Edinburgh Airport

The cancellations keep coming, as Gordon Dewar the chief executive of Edinburgh Airport, explains to us.

Speaking on Radio Scotland's Mornings programme he says: "The airport is relatively calm.

"We've seen another handful of cancellations which again are probably the result of aircraft being in the wrong place or crew being in the wrong place or out of hours."

He adds there is a pretty modest number of cancellations today.

In Edinburgh yesterday there were around 100 cancellations, about 50 outbound and 50 inbound, he says.

The airlines are trying to get the planes to where they should be and there's a real "scramble" for flights, Dewar adds.

Katy Austin
Transport Correspondent

Earlier this morning, Transport Secretary Mark Harper told the BBC he expects an investigation to be carried out by the UK Civil Aviation Authority (CAA) which will then be reported back to him.

We've now heard from Rob Bishton who is the interim CEO at the CAA who acknowledges "many customers" continue to experience flight disruption following yesterday's National Air Traffic Services' (Nats) technical issue.

“As part of our regulatory oversight of its activities, we continue to engage with Nats and once its investigation is fully complete, an incident report will be provided to the UK Civil Aviation Authority," Bishton says.

He confirmed the report's outcomes will be shared with the government.

We've just seen an update from London's Stansted Airport, which is now operating "a near normal flight schedule today" following yesterday's air traffic control fault.

Some delays and cancellations may still occur, a statement from the airport says, external, and it advises passengers to check the status of their flight before travelling to the airport.

It adds that terminals may be busier than usual at times today due to airlines working to accommodate passengers whose travel plans have been disrupted over the past 24 hours.

Joe Tidy
Cyber-security reporter

There's no suggestion at this stage that it is a result of a hack and the fast recovery would heavily suggest it isn't.

When a company goes back to manual pen and paper processes alarm bells ring in the cyber security world as this is often what happens when an organisation is locked out of their IT systems due to attacks like ransomware.

But the speed of recovery here makes this scenario seem unlikely as these types of cyber attacks lead to much longer delays and recoveries.

Also, history tells us that we don't need hackers to cause havoc to our aviation IT - multiple glitches and technical problems have created chaos in previous years.

Not many are on this scale of course but I remember covering a major outage in 2013 when no planes could land in any London airport. No hackers there though - a control centre simply failed to switch over from night mode to active day mode.

Image source, EPA

We have an update from British Airways, with the airline saying, like others, it is continuing to experience knock-on effects from yesterday's air traffic control outage, which includes unavoidable delays and cancellations today.

Customers on short-haul flights will be able to reschedule to an available service at later date free of charge, it said.

"We’ve apologised for the huge inconvenience caused, which was outside of our control and thank our customers for their patience as we work hard to get back on track," the airline's statement said.