Britain's stormy summer has increased pollution on its beaches, a Marine Conservation Society report has said.
Untreated sewage flows into the sea near many beaches after storms
Heavy rain swept pollutants such as raw sewage, refuse and farm waste into the sea - they left 71 UK beaches seriously affected in the first half of summer.
Of 553 beaches tested for bathing water quality standards this year, 16 failed. Last year, only two of 520 failed.
The society is calling on the government to warn the public about the risks of increased pollution.
Coastal pollution officer Thomas Bell said the extreme wet weather had undoubtedly contributed to this year's poorer results.
The report also suggested that only 86% of beaches were considered of a good standard, compared with 94% last year.
He said it was a problem for swimmers knowing when beaches had become temporarily badly polluted.
"We are calling on the government to provide public information on all bathing beaches, advising swimmers that coastal waters can be temporarily affected by increased pollution, with a consequent risk to bathers' health, after heavy rain," he said.
He added that special measures were needed to combat pollution including expanding the sewer system to handle large volumes of storm water and improving some 2,000 failing combined sewer overflows.
"Increased storm pollution is just one of the many growing pressures on our seas, and MCS is calling for a Marine Act to provide better protection and management for our seas and coasts," he added.