In a statement released via the League Managers' Association he said: "I started my West Ham United career when I left school in 1974 and have remained a lifelong fan. I have been incredibly proud to manage such a great club and my decision to resign has been very tough.

"The selection of players is critical to the job of the manager and I had an agreement with the club that I alone would determine the composition of the squad.

"However, the club continued to make significant player decisions without involving me. In the end such a breach of trust and confidence meant that I had no option but to leave. Nevertheless, I wish the club and the players every success in the future."

The LMA went on to cite "the club's unilateral actions around player transfers, without reference to their manager [which] have created irreparable damage to Alan's working relationship with the directors."

Richard Bevan, LMA chief executive, said: "The LMA has been working with Alan Curbishley over the past few days in an attempt to resolve his grievances with his employers. Sadly for West Ham United and Alan, reconciliation was not possible in the circumstances."

It is understood Curbishley had grown disillusioned at the club's transfer policy this season under the Icelandic owners, which had led to the departure of high-earner Freddie Ljungberg and the subsequent recent sales of Anton Ferdinand and George McCartney.

The Hammers also on Wednesday took the step of releasing an extensive statement - which was posted before the official announcement of Curbishley's resignation - defending the club's activities in the transfer market.

"The transfers of Anton Ferdinand and George McCartney along with the release of Freddie Ljungberg were right for the club and decisions had to be taken based on our best long-term interests," the statement read.

"In the past week, agreement could not be reached with Ferdinand on a new contract to replace his original deal that had just two years left to run while McCartney handed in a formal written transfer request after failing to resolve his personal reasons for wanting a move away."

West Ham chairman and owner Bjorgolfur Gudmundsson, meanwhile, maintains the east London club are heading in the right direction.

"In my first full season as chairman of this great football club, I can assure our loyal supporters that we are working hard to bring sustained success to West Ham United," he said

"Everyone, including the chief executive and board, is committed to this common goal.

"We have a long-term strategy that takes into account all aspects of West Ham United's past, present and future and we will not be deterred.

"Our fans can look forward to many positive years on and off the pitch."