Ryanair has sought to explain its controversial one carry-on bag rule, insisting it is necessary for safety reasons.

The move was prompted “false claims” made by a number of “poorly briefed” members in the European Parliament, Ryanair said.

Ryanair argues because it operates with very high load factors and because it encourages its passengers to travel with free of charge carry-on bags in order to avoid checked in bag fees, most passengers carry ten kilograms of luggage onto the plane.

This means that on a regular basis, “all of the overhead lockers and the storage space under the seats are fully used”, Ryanair said in a statement.

As a result, Ryanair cannot allow a second carry-on bag to be brought on board for passenger safety reasons.

Ryanair maintained an average load factor last year of 83 per cent, while IATA points to an industry average of 77.3 per cent for November 2012, the most recent figure available.

Ryanair spokesman Stephen McNamara said: “The inaccurate claims made by some member of the European parliament, claiming that Ryanair’s free of charge carry-on bag policy was designed to generate revenues were absurd and untrue.

“The purpose of Ryanair’s free of charge ten kilograms carry-on bag is to allow passengers to avoid our checked in bag fees.

“Three quarters of Ryanair’s 80 million passengers now travel without paying any checked in bag fees, while availing of our ten kilogram free of charge carry-on bag facility.

“This reduces Ryanair’s revenues and our costs.”

Earlier this week British Labour MEP Brian Simpson, chair of the European Parliament Transport & Tourism Committee, tabled a call for a new set of Europe-wide aviation rules.

This could see airlines forced to allow passengers to bring more than one bag onto a flight.

Simpson said that, while he was aware that cabin baggage rules had to reflect different aircraft types, his concern was that “certain airlines look to charge for everything”.

He added the commission needed to “help alleviate the cancer that is add-on charges which bedevil European aviation and leave passengers often angry, confused and with the feeling of having been robbed”.

Proposals are expected later this year.