More than a quarter of Britain’s top-rated beaches, including three in North Yorkshire, should be stripped of their Blue Flag status, campaigners said.

According to research by Surfers Against Sewage (SAS), 34 beaches are unable to comply with a requirement imposed by the Blue Flag programme to warn the public about raw sewage spilling into the sea Their list includes beaches at Filey; North Bay, Scarborough; and Whitby West Cliff.

Britain has 131 beaches which have passed strict tests to fly the flag – showing excellence in water quality and beach cleanliness.

But using the Freedom of Information Act, SAS found local authorities responsible for 20 Blue Flag beaches in England, two in Scotland, nine in Wales and three in Northern Ireland did not request real-time information on combined sewage overflow (CSO) discharge.

The campaign group said those beaches could not therefore meet a mandatory requirement to warn the public during and after emergency pollution events, such as sewage discharge from a CSO, which could pose health risks to bathers.

A spokesman for Keep Britain Tidy, which runs the scheme in England, said: “At Blue Flag beaches water quality is monitored by the Environment Agency during the bathing season and beach managers are required to display the results on the beach signage so the public can see them and make informed decisions about whether to enter the water.

“We cannot be present on every award-holding beach every day, and therefore if evidence is presented to us that calls into question that the high standards required are not being met, then we will investigate and take the appropriate action – even if that means withdrawing Blue Flag.”

“Since the awards for 2010 were announced in May we have reminded the beach managers of the Blue Flag criteria and their obligations to take the Blue Flag down when their beach is not meeting all the criteria,” the spokesman said