South West Water confirms sewage was pumped into sea off Polzeath beach in Cornwall, where PM and his wife have holidayed every year since 2010

David Cameron, chillaxing with his wife Samantha in Cornwall, presumably thought he was safe from a shower of excrement – at least until PMQs begins again in September. But the unlucky PM chose the wrong moment to bodyboard with his wife Samantha, as the surf was riven with diluted sewage.

South West Water confirmed to the Times that sewage was pumped into the sea on Sunday morning and on Wednesday afternoon off Polzeath beach, where the Camerons have holidayed every year since 2010. The couple were photographed bodyboarding for about an hour on Monday and Tuesday.

Campaign group Surfers Against Sewage issues alerts to warn people against entering the water because of the risk of infection. Untreated sewage is pumped into the sea as an emergency measure when heavy rain might cause the water to back into people’s homes.

David Smith, campaign manager for SAS, told the paper: “If the Camerons were swimming within the time frames of a spillage they might well be at risk. There could be anything from a small health risk such as skin, eye, ear, or throat infections to much more serious conditions such as E.coli or hepatitis, which can be present within raw sewage.”

In pictures of the pair, a drenched Cameron appears to have his mouth firmly closed. But Smith said the average surfer ingests 200ml of seawater for every surf, even if they mean to avoid it. “If surfers are using polluted waters the chance of them becoming ill raises significantly,” he said.

Cameron is no stranger to holiday health hiccups. Earlier this month, the PM was treated for an ear infection called otitis – known as swimmer’s ear – which he picked up surfing in Portugal. Last year, in Lanzarote, he was stung by a jellyfish.