Newcastle midfielder Joey Barton has been told he can leave the Premier League team on a free transfer after his stormy relationship with the club reached breaking point.

Barton was already unhappy with Newcastle's decision to allow captain Kevin Nolan to join West Ham during the close-season and his mood wasn't improved by the recent breakdown of talks over a new contract.

The 28-year-old showed his frustrations with Newcastle owner Mike Ashley and the club's directors with a series of angry posts on the micro-blogging website Twitter.

Writing after Sunday's 3-2 friendly defeat at Leeds, Barton claimed another Twitter post from Newcastle team-mate Jose Enrique, which led to the Spaniard being fined after he accused the club of lacking ambition, was typical of the unhappy atmosphere among the players.