The 23-year-old, who was granted one final chance to rescue his career by City manager Stuart Pearce last summer, was yesterday offered a new contract worth around £30,000 a week having rejected the club's opening gambit 10 days previously. Once again, however, he turned down the deal and, following talks with Pearce at the club's Carrington training ground, he made his displeasure known by submitting a formal request to leave.
Barton's impetuous actions have stunned the City faithful, and not only because he had appeared to have matured both on and off the field this season, to the extent that Middlesbrough, Charlton Athletic and even local rivals Manchester United have all been linked with a move for the tenacious Liverpudlian.
Last July he was almost sacked by the club having been involved in a hotel brawl with a 15-year-old Evertonian during a pre-season tournament in Thailand. Only the intervention of Pearce, who admitted that a night in a Bangkok prison may have served to do the midfielder some good, led to the leniency of merely being sent home early in disgrace.
The Bangkok brawl prompted City to seek professional help for Barton, who was fined six weeks' wages and told he was on a final warning in December 2004 for stabbing a lit cigar into the eye of young team-mate Jamie Tandy during the club's Christmas party.
He was sent to the Sporting Chance clinic, given anger management lessons and counselled during his brother's trial for the racist murder of Merseyside teenager Anthony Walker, a killing for which Michael Barton recently received an 18-year prison sentence.
Barton has regularly expressed his gratitude to Pearce and the club since the summer and has repaid them in this season's performances. His gratitude, however, has stopped short of extending a contract that has only 18 months left to run and currently earns him around £17,000 a week.
The midfielder, who has recently left the SFX agency to join Monaco-based agent Willie McKay, is understood to feel that City's offer belittles his contribution to the encouraging progress made under Pearce and wants to double his current salary before committing to a new deal.
Despite handing in a transfer request only 24 hours before the January window closes at midnight tonight, City, who allowed Robbie Fowler to join Liverpool on Friday, will not bow to his demands even if a firm offer arrives today.
The club believe Barton's actions are a bargaining tool and swiftly made their position clear in a statement last night. It read: "The manager has publicly stated his desire to keep the player at Manchester City Football Club. A second round of negotiations between the club and the player's representatives took place yesterday and Manchester City wishes to continue those talks."
l City last night reached agreement on a £6m deal for Heerenveen's Greek striker Georgios Samaras, who could make his debut at home to Newcastle tomorrow.