A Ryanair passenger on a Brussels-Berlin flight was prevented from boarding the budget airline after launching into an angry tirade at a boarding-gate attendant.

The American man, said to be called Rudy Kendall, was irked after learning he had to pay €50 at the check-in desk to print his boarding pass, having not done it himself. The 'print or pay' policy has been in place at the low cost airline since 2011.

Mobile phone footage, which the passenger appears to have filmed himself, shows him becoming increasingly agitated after he is told of the cost for printing his boarding pass at the airport.

He demands that the attendant, working for Ryanair's handling agent Aviapartner, call her supervisor and when she does not respond he shouts: “I’m paying your salary, what kind of customer service is this? I'm a customer, lady. I'm asking your supervisor's name so I can speak with your supervisor because I'm unhappy with the way you're performing your job.

"You tell me I have to pay €50 for a flight I'm already checked in on."

Abusive behaviour will not be tolerated by the airline (Getty Images)

As the attendant gives a slight smile while picking up the phone – presumably to security – he says: "Is there something funny here? What's the joke? Is it your attitude?

"You have a bad attitude. You have no business working here and dealing with customers."

After berating her for more than three minutes at a packed boarding gate, a fellow passenger wades in to diffuse the situation and asks the man in the video to “stop harassing” the attendant.

He responds by calling the man fat and bald, telling him, "You're nothing man, you're nothing."

Witnessing the argument the attendant buries her head in her hands and starts to cry. As other passengers attempt to help, he tells them to mind their own business.

The man, who is black, later claimed later he was a victim of "mob tendencies by Europeans against dark-skinned foreigners".

However, a witness named Philipp said racism did not play a part in the incident.

John Walton, deputy editor at Runway Girl Network, told the Independent that passengers sticking up for staff is unusual. He said: “We’ve seen recently that some passengers are sticking up for other passengers when they feel that airline staffers or local authorities aren’t treating them right. But it’s unusual for other passengers to feel like they need to stick up for airline staffers, though I’m heartened that they did in this case, since the angry passenger is clearly abusive.

“Unfortunately, staff working for Ryanair and airlines like it are at the sharp end of the consequences of airlines treating customers with contempt.

“While there’s no excuse for the way this passenger behaved, Ryanair’s policies for charging to print boarding passes are excessive and punitive. Regular Ryanair flyers know how not to get stung, but if the airline wants to attract international passengers then it needs to consider its own policies’ role in the escalation of this situation.”

A Ryanair spokesman said: "Our handling agent at Brussels Airport, Aviapartner, is looking into this matter. We will not tolerate unruly or disruptive behaviour at any time."

"Terms of travel are agreed to at the time of booking and all customers are sent three reminder emails and an SMS text message advising them of the need to check-in. Over 99.5% of customers check-in online and travel without issue.

"Customers who check-in online but fail to produce their boarding pass are subject to a €15 boarding card reissue fee. Customers who fail to check-in online are subject to a €50 airport check-in fee."

A spokesman for Aviapartner said: “A passenger who had failed to check-in on-line (as required) became disruptive during the boarding of this flight from Brussels to Berlin and refused to pay the Airport Check-in Fee due, distracting the gate agent from her duties and disturbing other passengers.