It has been a busy week for the plankers, in which they have suffered their first casualty, gained 100,000 converts and prompted a statement from Prime Minister Julia Gillard. In the early hours of Sunday morning, 20-year-old Australian Acton Beale fell seven storeys to his death from the balcony of an apartment block in Kangaroo Point, Brisbane. He and a friend had been performing planks on their journey home from a night on the town. The planking craze had only truly exploded in Australia two days earlier, when police arrested another young man for planking on the hood of an unoccupied police car. Nate Shaw, a 20-year-old, pointed out that he had done no damage and hurt no one, but was nonetheless charged with being found - quite literally - on police property without excuse.

The arrest made headlines, and the Planking Australia Facebook page grew almost overnight from 8000 fans to well over 100,000. But dedicated hipsters will have heard of planking years ago. Though it is now biggest in Australia, it is an English - some would say, quintessentially English - creation. It began 14 years ago with a pair of bored kids. Gary Clarkson, then 15, and his friend Christian Langdon, 12, would perform the plank in public places, amusing one another and baffling onlookers. Back then, it was known simply as the Lying Down Game.

It was a pointedly pointless way for the boys to pass the time. As Clarkson puts it: "It was just a really stupid, random thing to do." For its first 10 years planking spread at a snail's pace, from Clarkson and Langdon to their friends at school and, after a while, on to other kids from the neighbourhood. Then, in 2007, when the pair created a Facebook group for their game, the pace accelerated. Soon, they had a few thousand followers. Photographs of plankers trickled in from all over the world: American plankers on the tops of their televisions, British plankers in trees, and Europeans on country roads and the banks of fjords. The craze began to garner its first major press coverage in September 2009, when a group of seven accident-and-emergency staff were suspended pending disciplinary hearings for playing the game while on a night shift at the Great Western Hospital in Swindon.

They had been planking on resuscitation trolleys, ward beds, floors and even the helipad. They might not have been caught had they not then posted the photos to Facebook, under the slightly self-defeating name The Secret Swindon Emergency Department Group. An employee of the hospital's governing body told the press: "It reflects badly on the department and some people may lose their jobs." Things escalated. A few days later, in Stoke-on-Trent, a mass gathering of plankers for a simultaneous lie down attracted more than 100 people.

The photos posted to Facebook became bolder and more bizarre. One audacious airport worker performed the plank in the idle engine fan of a jet plane. It's not clear - and Clarkson and Langdon don't remember - where exactly the idea for planking came from. Some commenters have linked the practice to the 1995 video for the Radiohead song, Just. In the video, a man lies down on a busy London road and a crowd of strangers gather to try to understand and help him.

He refuses to move, or to tell them why he's lying there. They persist, and eventually he relents. He tells them - but not us, the viewers - and all we see, in a long slow punchline of a shot, is that now the entire crowd is lying down on the pavement as well. Whether the video is the inspiration or not, it captures something of planking's essence. Loading "People generally think you're mad," as creator Gary Clarkson puts it. "That's sort of the point." The Guardian