Alan Curbishley was "gutted" to walk out on West Ham but felt he had no other option after claiming he was undermined by the Barclays Premier League club's transfer policy.

Curbishley's main problems were behind the scenes, however, and under the direction of the Icelandic owners and new technical director Gianluca Nani, high earners such as Freddie Ljungberg departed over the summer as the squad, and wage bill, was cut down to size.

Anton Ferdinand and then fellow defender George McCartney - on transfer deadline day - were late departures from Upton Park against Curbishley's long-term plans for the team.

That proved a step too far for the 50-year-old, who had started his playing career at Upton Park.

"I felt I could just not stand by and let what happened [pass], especially at the weekend, so I made a decision," Curbishley told Sky Sports News. "Some managers may not have taken this action, but I could not sit around and be silent on it.

"I am absolutely gutted I have had to come to this decision."

Curbishley - appointed in December 2006 and who presided over what was a remarkable escape from relegation that season - added: "I have overall say on players who come in and out of the club, although I have no say on transfer fee or any financial negotiation with the players. That has been made quite clear in my contract.

"On Sunday morning, I went into a meeting with [chief executive] Scott Duxbury at Upton Park perhaps hoping to bring some loans in, and I was told I would not be in that position unless someone left the club.

"I said straight away, 'well let's go home then because I do not want anyone to leave'.

"I was just quite happy we get on with it as we are, especially coming off the back of the result against Blackburn.

"I was quite happy to stick with it, even if it meant I could not improve it.

"The criticism I have had, I took that in a dignified manner," he added. "But I was taking it all on the chin, and trying to turn things around.

"I think a lot of fans would have seen I was doing a decent job.

"Staying up and finishing 10th with the injury problems we had as a team was creditable, but I know they wanted more and I just got a little glimpse of that at the weekend with one or two more players returning, we would be on the right road."

Curbishley's departure was announced on the West Ham official website earlier this afternoon, and the former Charlton boss later released a statement of his own, hitting out at the "breach of trust and confidence" at the club.

He said: "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."

A club statement earlier defended the transfer policy and insisted that it was necessary to alleviate the financial strain on the club.

The search will now begin for a fifth West Ham manager in seven years.

Former Hammers defender and current coach of Croatia Slaven Bilic is among the favourites to succeed Curbishley. The colourful Croat has repeatedly stated his desire to manage in England at some stage and his stock has risen since he led his country to the Euro 2008 quarter-finals.

Other contenders include former England manager Glenn Hoddle and one-time England contender Sam Allardyce, while Roberto Mancini and Frank Rijkaard are also in the running, according to some bookmakers.