Secret of Britons' dirty bedsheets is out - and it's too dirty to be exposed.
The survey of 1,029 men and women aged 18 and over, conducted by Sheilas' Wheels home insurance, has found that half a million Britons admit to only washing their bed sheets three times a year.
One in six people also admitted to waiting at least four weeks before washing their bed sheets, reports The Daily Express.
Dr Lisa Ackerley, an environmental health practitioner, said: "An unsavoury 42 per cent of the British population regularly enjoy a bite to eat in bed."
She added: "With a tenth of the weight of a two-year-old pillow comprised of dead skin and dust mites it's no surprise that your bed can become a minefield of bacteria, viruses, sweat and hair which can cause or exacerbate asthma.
"America's Environment Health and Safety Online found a typical used mattress may have anywhere from 100,000 to 10million mites inside.
"Washing your bedding takes time and effort, but to reduce levels of unwanted organisms and mites you need to wash your bed linen at least once a fortnight, preferably once a week."
Under-25s were found to have the dirtiest bed sheets, with one in 10 admitting to washing theirs only six times a year. While over-55s aired their dirty laundry on average three times a month.