"I was playing for the puzzles and the stories, but it was only a few days ago that I thought I was in with a chance," said Mr Darley.

"As I pulled the Cube from the sticky, wet clay, and even afterwards as I was waiting to return the Cube, all I could think about was how bizarre the whole thing really was."

Elaborate clues

Perplex city is one of a number of alternate reality games (ARGs) that blur the boundaries between the real and virtual worlds. The first recognised one was The Beast, developed as part of a marketing campaign for the film AI.

They use real world events and clues planted on the internet, television and newspapers to guide players on a real-life treasure hunt.

Perplex City also used puzzle cards, bought in shops and on the internet, that contained optical illusions, cryptography, and riddles. The rarest cards have traded hands for more than £200 on online auction sites.

Music with clues in the melodies and real life parties, often with elaborate scenarios, also led gamers towards the final goal.

Perplex City has been running since April 2005 but speculation about the location of the hidden object has escalated in recent weeks.

Following a recent live event, Mr Darley tracked the cube down to Wakerly Great Wood, Northamptonshire at 0400 GMT on 02 February. To claim his prize and end the game he returned the cube to the Perplex City headquarters in London.

A new Perplex City game will start later this year.