A Ryanair flight heading to the UK from Greece took off without dozens of its passengers on board due to 'mega queues' at passport control. 

Authorities at Athens International Airport were forced to step in after 20 to 50 travellers booked onto the flight to London Luton were left stranded on Sunday. 

Ryanair blamed border delays for the chaos, while the airport said it had been experiencing congestion linked to the introduction of the EU's Entry Exit System (EES). 

The new requirements, which came into effect on April 10, mean UK passengers must register biometric details such as fingerprints and facial recognition images when entering the Schengen Area. 

Milo Boyd, a travel writer, said there was a 'mega queue' of several hundred people at both the airport's security checks and passport control. 

He and his wife managed to make it through just ten minutes before the gate closed, but he said furious passengers were pleading with Ryanair to let them on the flight.  

'These poor people were pleading with the Ryanair staff to let them through - one guy was crying, another guy looked like he was about to explode,' Mr Boyd told the BBC. 

He added there were passengers who had missed their flight shouting 'you can't do this' as frustrations grew. 

One passenger Ian Collins tweeted Ryanair, saying it was 'utterly disgraceful you left my daughter (and half your passengers) at the gate in Athens today'. 

It is understood that the flight on Sunday departed an hour late after the missing passengers' bags were unloaded from the plane. 

And it is not the first time travellers have missed their flights as a result of chaotic airport queues.

British airline passengers were recently left behind in Toulouse after a plane took off without 150 of its passengers on board. 

Passengers were unable to reach their gate in time for flight FR282 to London Stansted on May 30.

One woman travelling on the plane said the situation in the airport was 'pure chaos', with delays beginning after security.

The passenger said around 400 or 500 people were all queueing in this area, and there was no real organisational system in place.

Meanwhile, a Ryanair flight from Milan Bergamo to Manchester took off on April 16 without a number of its passengers on board.

Adam Hassanjee, 18, from Bolton - who was one of the stranded passengers - told the BBC: 'We were waiting for an hour and a half and weren't moving.

'Then we see the plane leave and got told we have to go and book our own flight back.'

Reports suggest around 30 people were left stranded, although Ryanair did not confirm exact numbers.

A spokesperson for Athens International Airport said: 'As is currently the case at many European airports, passenger flows on certain routes may experience increased processing times as new border-control procedures continue to be implemented and refined.' 

A spokesperson for Ryanair added: 'Due to delays caused by border control at Athens Airport on 14 June, a number of passengers booked to travel from Athens to London Luton were not in the boarding gate area when boarding for their flight closed and missed their flight from to Athens to London Luton. 

'All passengers that were at the boarding gate when this flight from Athens to London Luton boarded, travelled without incident.'