A plastic bag recycling group has sparked a furious row with the makers of degradable bags after claiming degradable bags encouraged littering and undermined recycling.

Symphony, which last year produced enough plastic for five billion degradable bags, accused European Plastic Recyclers (EuPR) of "fundamentally misunderstanding" degradable technology.

EuPR - which represents companies that recycle regular carrier bags - said new degradable bags, which break down to nothing over a period of months, wasted the stored energy in plastic bags, "polluted" recycling streams and encouraged people to litter.

"Public attention will be diverted from recycling by people thinking 'it will degrade by itself'," said a spokesman. "This thinking will damage the recycling rates achieved after decades of effort."

But Symphony said these claims were "alarmist nonsense ... worthy of King Canute's foolish advisors".

"There is not a shred of evidence for the allegation that degradable plastic has encouraged littering," said a Symphony spokesman. "Degradable plastic can also be recycled during its useful life, and if a carrier bag has not been recycled within 18 months it probably never will be ."

Symphony added its products could be recycled alongside conventional bags but conceded other degradable bags or compostable ones, such as those made of corn starch, could not.