Westminster City Council has launched an SMS service to inform users of the nearest public toilet.

Users text 'toilet' to 80097 and the service determines their location and automatically finds the nearest public toilet. The 'SatLav' system charges 25p for each text.

Locations include the council's 40 public toilets, plus those of the Greater London Authority, London Underground and some major department stores.

Westminster City Council said that the location service is designed to cut down on the amount of "street urination".

"Up to 45,460 litres of urine is at risk of ending up in the city's streets and alleyways through irresponsible and antisocial behaviour," said the council in a statement.

The SatLav service was the winning entry in Westminster City Council's innovation competition, won by Gail Knight, a 26 year-old student from Clapham Junction.

"From today nobody should ever get caught short again, and we understand how important that is, be it for a young mum with children in tow, older people or friends on a shopping trip or night out," said Westminster councillor Alan Bradley.