Festival goers are leaving tens of thousands of tents behind in the mistaken belief they will be donated to the homeless and refugees, a charity has warned.

The vast majority of the sea of rubbish abandoned in fields after events such as Reading and Leeds this bank holiday weekend is “avoidable plastic pollution” that will be taken to landfill.

Green campaigners said the idea that sleeping bags, tents and chairs would be put to better use was “complete nonsense.”

Matt Wedge, director of Festival Waste Reclamation & Distribution, a charity set up to divert usable “waste” towards vulnerable people, said: “There is a common misconception that leaving your tent is like making a donation.

“It’s simply not the case. We co-ordinate local volunteers and charity groups and take as much as we can for the homeless and refugees in Calais and Dunkirk but realistically, up to 90 per cent gets left behind.”

Teresa Moore, director of environmental campaign group A Greener Festival, said her own research indicated that a large proportion of festival goers believed their tents would be given to charity.