David Cameron and his wife Samantha may have gone surfing in sea water polluted by diluted sewage during their holiday in Cornwall.

South West Water confirmed to the The Times that untreated effluent was pumped into the sea twice last week off Polzeath beach following bouts of heavy rain.

The Prime Minister and his family visited the beach on Monday and Tuesday afternoon last week, but are believed to have visited the beach everyday. They take their annual holiday in the area every year.

The campaign group Surfers Against Sewage released a warning message through the Safer Seas Service app that the Combined Sewer Overflow at Polzeath beach was being activated on Sunday and Wednesday, according to the newspaper.

Swimmers are advised not to enter the sea for 48 hours after the effluent is pumped out into the water.

David Smith, the campaign manager for SAS, said: “If the Camerons were swimming within the time frames of a spillage they might well be at risk.