A charge is being introduced to use toilets at a London landmark following a decision by the London mayor.
The Greater London Authority (GLA) said each person would be charged 20 pence to use the public toilets in Trafalgar Square to contribute to running costs.
An increase in customers using a nearby cafe's toilets could be of "additional benefit", according to the GLA which shares the cafe's profits.
A critic has said the charge should not be a "money-making scheme".
The mayoral decision document said the toilets on Trafalgar Square, which are open seven days a week, cost £149,000 a year to manage, plus additional costs for repairs which amounted to about £2,000 in the last year.
Boris Johnson's office added the charge should generate around £100,000 a year as approximately 360 people use the facility per hour.
The GLA document said although toilets in the cafe on Trafalgar Square were free and for the use of customers, the introduction of the charge "may increase the number of customers that use the cafe, which will in turn increase the turnover of business.
"As the GLA has a profit share arrangement for this cafe it will be of additional benefit to the GLA".
Labour London Assembly Member Murad Qureshi said: "Whilst I don't object to charging for public toilets if the money is used to keep them clean and safe, it's a totally different matter if it's being done to push people into spending more money at a City Hall run café just so they can use the loo.
"Toilets should be a public convenience, not a money-making scheme."
The mayor's office said the toilets were unavailable for periods of time due to repairs or cleaning often due to vandalism and anti-social behaviour and it was hoped the new charge would act as a "deterrent to prevent future misuse".
As one of the only free toilets in the area, the GLA said the toilets have had their drainage blocked, doors damaged and there were reports of people sleeping in the cubicles.
The date the turnstiles will be installed has not been announced by the GLA. The disabled toilet facilities will remain free of charge.