A poll suggests that more than half a million Britons only wash their sheets three times a year
, allowing some 10 million bugs and dust mites to settle in for a night cap alongside them.
Londoners are the most frowzy - almost a quarter of the capital's inhabitants opt for the four-monthly approach - while just eight per cent of house-proud people in Northern Ireland are the same. One is six do it only once a month.
The staggering statistic comes at a time when most of us are spending 49 hours a week under the covers to avoid the cold snap.
Despite forking out an average £1,020 for a bed and linen, almost half of people surveyed admitted to regularly eating in bed
and running the risk of encouraging further creatures.
The poll carried out by insurance firm Sheilas' Wheels revealed that under 25s had the dirtiest sheets with one in 10 polled washing them only six times a year. The elders among us, in contrast, aired their dirty laundry an average of three times a month.
Jacky Brown, of Sheilas' Wheels said: 'With the cold weather making our beds more irresistible than ever, Brits are currently spending more than 49 hours a week sleeping in. 'The bed is one of the most used and expensive items in the home.
'So it's astonishing that more people aren't keeping it clean, with many beds being used as an alternative to the kitchen table for a place to breakfast or snack.'
Environmental health expert Dr Lisa Ackerley said: 'It's estimated that 10 per cent of the weight of a two year old pillow is comprised of dead skin and dust mites.
'So it's no surprise that your bed can become a minefield of bacteria, viruses, sweat and hair
which can cause or exacerbate asthma.
'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.'