The travellers were due to fly from Toulouse to London Stansted on 30 May. According to passengers, the problem wasn't a delayed train to the airport, an oversized suitcase or a last-minute dash through the terminal. It was simply a queue that wasn't moving.

One traveller described hundreds of people packed into the border control area as departure times came and went, according to Euroweekly News. By the time many finally made it through, their flight had already left.

Passengers who boarded the aircraft later reported hearing a pilot's announcement stating that around 150 people had been unable to reach the gate in time.

Ryanair blamed a shortage of border control staff and said all passengers who arrived before boarding closed were allowed to board.

The incident comes as airports across Europe prepare for a busy summer and adapt to new border procedures that many in the aviation industry fear could put additional pressure on already stretched systems.