The first council in the UK has said it is planning to tell residents to stop recycling mixed plastic, sparking fears that years of progress on reducing black bag waste is on the verge of going into reverse.

It comes as the Environment Agency is understood to be investigating the plastics recycling industry over claims that millions of tonnes of plastic is never actually recycled, meaning consumers may have been wasting time separating plastic waste.

Plastic recycling waste has been building up in the UK since China stopped importing it last year, with the situation now so bad that councils have now started cutting plastic recycling services.

Swindon has said it wants households to put mixed plastic items, such as yogurt pots and plastic trays, in the bin with regular waste.

Instead of recycling it is proposing to incinerate it along with other household rubbish. The Environment Agency is said to be investigating claims that plastic meant for recycling is being left to leak into rivers and oceans.