Ryanair's chief executive caused howls of protest today when he suggested that the airline may charge passengers £1 to use its toilets.

Michael O'Leary said that the carrier had been investigating fitting coin slots to the doors of aircraft toilets, similar to those installed at train stations.

“One thing we have looked at in the past and are looking at again is the possibility of maybe putting a coin slot on the toilet door so that people might actually have to spend a pound to spend a penny in future,” he told BBC Breakfast this morning.

“We are always at Ryanair looking at ways of constantly lowering the cost of air travel to make it affordable and easier for all passengers to fly with us.”

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Consumer groups reacted angrily to the proposal. Rochelle Turner, head of research at Which? Holiday, said: "It seems Ryanair is prepared to plumb any depth to make a fast buck and, once again, is putting profit before the comfort of its customers."

She said that the plan could backfire: "Charging people to go to the toilet might result in fewer people buying overpriced drinks on board, though - that would serve Ryanair right."

Ryanair would not be breaking the law if it introduced the charge, said the Civil Aviation Authority, which regulates the industry.

The proposal also sparked an online debate among pilots as to whether crew would also be required to pay to use the toilets. “How many 'tokens' will the crew receive a day? 1 per sector? 1 per day?” said one on the Professional Pilots Rumour Network.

Ryanair has already caused upset this week when it announced plans to close check-in desks and raise baggage charges.

A spokeswoman initially told The Times that the carrier had been investigating a toilet charge. “The situation is that there is no legal requirement for an aircraft to have a toilet onboard, so if an airline does have a toilet they can charge to use it," she said.

“Ryanair is legally able to do this."

After the controversy erupted, Mr O’Leary’s team appeared to backtrack.

A statement issued by the Ryanair marketing team shortly after midday said: “Michael makes a lot of this stuff up as he goes along and while this has been discussed internally there are no immediate plans to introduce it.

“Ancillary revenues, all of which are avoidable, help to reduce the cost of flying Ryanair and passengers using train and bus stations are already accustomed to paying to use the toilet so why not on airplanes?

“Not everyone uses the toilet on board one of our flights but those that do could help to reduce airfares for all passengers. Then again, maybe O’Leary was just taking the p*** this morning.”

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