Three in 10 smokers wrongly believe cigarette butts are biodegradable, according to research.

A study of 1,000 smokers revealed 38 per cent have tossed a stub down a drain, with three in 10 believing this to be an ‘appropriate’ method of disposal.

More than a third (34 per cent) even thought binning them in drains would accelerate the breakdown of the cigarettes.

Key reasons for discarding fag-ends this way include being in a rush (23 per cent) or simply feeling that everyone else does it so they may as well to the same (15 per cent).

The study was commissioned by Keep Britain Tidy, which is working with a London pub to highlight cigarette-related litter problems, after its data revealed hospitality premises see among the highest volumes of discard butts.

'The White Swan', in Twickenham, is being renamed to 'The Poisoned Swan' to highlight the impact dropping butts down drains has on wildlife.

New patron, Johnny Vegas, said: "It seems a lot of smokers don’t realise they’re doing more harm than good by disposing of their butts in drains.”