For some it is lullabies; a few wafty verses of Rock-a-Bye Baby or Twinkle, Twinkle, Little Star, perhaps. For others it is a spot of sheepular arithmetic, a cup of warm milk, or a bedtime story. For football's enfant terrible Wayne Rooney, however, it is a vacuum cleaner.

This has nothing to do with Liverpool brothels, suction techniques or seedy kiss-and-tells; rather, it concerns the news that young Rooney cannot drift off to sleep without the distinctive drone of a vacuum cleaner. If a vacuum cleaner is not available, he will settle for a hairdryer. Not a sentence I ever imagined I would write.

This illuminating revelation arrives courtesy of Rooney's autobiography, My Story So Far, in which he discloses: "I not only like to have the TV and light on to help me sleep but also a vacuum cleaner. Failing that, a fan or hairdryer will do. I've ruined so many hairdryers by letting them burn out. So far I haven't set fire to anything. Coleen hates it." One's first response is to extend one's deepest sympathies to Coleen. One's second is to think, "Is Rooney bonkers?"

"I can't say it's abnormal, but it is atypical," says Stephen Emegbo, a sleep physiologist at the Sleep Research Centre at the University of Surrey. "Most people need quiet and calm when they're trying to get to sleep." It seems, however, that some people require certain familiar sounds to guide them to the "land of nod" (technical term). "It's the process the brain needs to initiate sleep," explains Emegbo. "An example would be town people who go to the countryside and have difficulty getting to sleep because they can't hear cars. Their brain says, 'Where's that little background noise?' even though they've probably never identified it before."

Whether we're aware of it or not, we all have certain routines that prepare us for sleep - be it plumping up pillows, or listening to the World Service before we turn out the light. For someone who needs to hear particular sounds before they can sleep, it is, according to Emegbo "very similar to when a child needs a lullaby."

Rooney's particular sleep-inducing fetish has more hazardous implications than most, however. One wonders how he convinced the elite hotels of Germany of his drone requirement while in the country for the World Cup. Vacuum cleaners, it should be noted, are rarely provided in the mini-bar or available via room service.

(This is confirmed by Wayne Munnelly, Travelodge "director of sleep", who believes it is unlikely that a hotel would permit a guest to keep a hairdryer running all night: "We wouldn't recommend leaving any electrical appliances like vacuum cleaners or hairdryers switched on while asleep or out of the room given the safety risks.")

But arriving hot on the heels of other members of the England team's obsessions - David Beckham's passion for neat lines and Steven Gerrard's fervour for hand-washing - this is shaping to be something of a trend. One can only imagine what revelations are to come: Peter Crouch's fastidiously organised cutlery drawer? John Terry's colour-coded wardrobe? Frank Lampard's pant-ironing fixation? The mind boggles.