Barton, 25, stubbed a lit cigar in the face of trainee Jamie Tandy at Manchester City's Christmas party in 2004.

Tandy, 23, is now pursuing a civil claim for damages against the Newcastle player, his legal representative's confirmed.

He claimed he suffered a "major psychiatric deterioration" following the assault which he said ultimately forced him out of the game at the top level.

Matthew Clayton, of Manchester-based law firm Ralli, said: "Mr Tandy is a client of ours and we are in the process of launching civil proceedings.

"As a result of the assault by Joey Barton our client has suffered a major psychiatric deterioration in his health that has destroyed any chance he may have had of playing professional football at a high level.

"Understandably this is a high-profile case and at this stage we are unable to comment further."

Tandy was released by Manchester City after he broke his leg while playing on loan with a Danish club.