Low-fare airline Ryanair is considering charging passengers to use the toilets on its planes, it was revealed today.
Customers of the Irish no-frills carrier might have to fork out £1 to "spend a penny" on flights, Ryanair's chief executive Michael O'Leary said.
Which? Holiday magazine condemned the plan, saying Ryanair was "plumbing the depths".
Speaking on the BBC1 Breakfast programme, Mr O'Leary said: "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 went on: "We are always looking at ways of making air travel cheaper. We are all about finding ways of raising revenue so we can keep lowering air fares."
Asked if this meant passengers being charged as much as £1 for a loo visit on Ryanair flights, Mr O'Leary replied: "I don't think there is anybody in history that has got on board a Ryanair aircraft with less than a pound."
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.
"Charging people to go to the toilet might result in fewer people buying overpriced drinks on board, though - that would serve Ryanair right."
Last week, Ryanair announced it was to shut all check-in desks at airports by the end of the year, with all passengers having to check in online instead.
The Irish budget carrier also charges for hold luggage and - like other low-fare airlines - charges for on-board food and drink.