Furious Frenchmen are threatening to turn the Seine into a sewer this Sunday in a bizarre protest against the eye-watering costs of Olympic preparations.

The movement, cheekily dubbed #JeChieDansLaSeineLe23Juin (I’ll poo in the Seine on June 23), has gained traction after Paris Mayor Anne Hidalgo boasted she’d take a dip to prove the river’s cleanliness.

Hidalgo, however, has now back-pedalled on her pledge, conveniently citing the hastily-called French elections as reason to postpone her plunge.

A staggering £1.2 billion has been poured into purifying the Seine for Olympic swimmers and triathletes, as the river prepares to host key events during the Games.

With just five weeks until the Games, recent tests revealed alarming levels of two types of faecal bacteria, including E.coli, falling short of Olympic standards.