The secret to a performance by the illusionist David Copperfield has been revealed after a Kent man launched a negligence lawsuit against the performer.

Copperfield was forced to reveal how he carries out one of his signature tricks after Gavin Cox, who is from Broadstairs, alleged he suffered lasting brain and body injuries after agreeing to take part in one of his Las Vegas shows.

Mr Cox, 57, said he has not worked since he fell over while being led through a secret passageway at the MGM Grand during the "Lucky #13" illusion in 2013.

He was one of a number of randomly-chosen participants taken from the audience who was ushered through passageways inside and outside the hotel in time to "reappear" during the show finale.

Mr Cox claims he was injured after he was "hurried with no guidance or instruction through a dark area under construction" which led to him falling

He was taken to hospital with a dislocated shoulder but claims he suffered chronic pain, headaches and confusion when he returned to the UK.

Copperfield's lawyers lost a bid before the trial to close proceedings to the public to avoid giving away the secret to his illusion.

MGM Grand Hotel attorney Jerry Popovich said on Tuesday that the illusion is no longer used to close the show.

Copperfield's friend and executive producer Chris Kenner said the trick had been performed by the magician thousands of times over 20 years.

He admitted audience members were told where they had to go while they were running the route.

However, he declined to say whether the route was dangerous.

Mr Cox and his wife, Minh-Hahn Cox, are seeking unspecified damages.