David Copperfield forced to reveal his secret tricks in court

World-renowned illusionist David Copperfield has been forced to reveal his trade secrets during a lengthy legal battle.

London chef Gavin Cox has launched legal action against the magician, claiming he was left with permanent brain damage while taking part in an illusion in Las Vegas.

Cox, 55, says he suffered a nasty fall at the MGM Hotel and Casino in 2013 as he was participating in Copperfield’s famous “disappearing audience” trick.

The illusion requires the volunteers from the audience to run through a secret passage, as Cox explained to The Daily Mail.

"It was like a fire alarm went off. They were saying 'Hurry! Run, run, run," he said.

"As I went around a corner, my feet slipped from underneath me and I hit the ground."

Copperfield and MGM have both denied Cox's allegation, contending that his injuries were caused by "pre-existing and/or other related medical conditions".

"The illusion has been performed for more than 15 years and with more than 100,000 participants. The history of the show speaks for itself. We deny all allegations." Copperfield's lawyer told the Daily Mail.

Here’s how David Copperfield's disappearing audience trick works:

• Copperfield throws 13 inflatable balls into the audience. Members of the public who catch one are called onstage

• The 13 participants are suspended in a cage and given torches to shine back at the audience

• The volunteers are then taken through a secret passage and outside the theatre, with Copperfield lifting the cover to reveal they are gone

• They then 'reappear' at the back of the stage still holding the torches they were given by Copperfield - to the surprise of the audience.