DIRTY duvets may be riddled with a mixture of mites, skin scales and pollen grains, according to research carried out in Worcester.

More than 40 per cent of Britons admitted they didn't wash their duvets every six months as recommended by experts, a survey found.

Tests carried out on 10 dirty duvets at the University of Worcester found they contained up to 20,000 live house dust mites.

Lab tests revealed that bacteria, fungal spores, stains and dust mite faeces were also lurking in the bedding.

The worst example - possibly the dirtiest duvet in Britain - hadn't been washed for 11 years.

It contained hidden fungal spores and 45g of debris including skin scales and house dust mite faeces.

Professor Jean Emberlin, director of Worcester University's national pollen and aerobiology research centre which carried out the research, said: "This has implications for health as contaminants can cause symptoms of asthma, rhinitis and conjunctivitis and irritate existing cases of eczema."

Seven of the 10 duvets tested had never been washed - two of which were more than a decade old.