REVEALED: Curbs quit West Ham because club officials tried to sell Ashton to Spurs and Bellamy to City behind his back

Sportsmail online understands that on discovering that Ashton had been offered to , and Bellamy to the new Arab owners at , on the final day of the transfer window, Curbishley considered it time to walk.

Offered to Spurs: Dean Ashton

Touted to City: Craig Bellamy

The former Charlton manager, who has been in charge at Upton Park since December 2006, had become frustrated with the club's unrealistic expectation to finish in the top seven of the Barclays Premier League.

Selling behind his back: Alan Curbishley has resigned as West Ham boss

If they expected him to finish so highly in the league, Curbishley must have surely questioned why were they selling his best players without his knowledge?

The 50-year-old held a series of meetings with the Upton Park hierarchy and after a final summit with Hammers' chief executive Scott Duxbury - to 'clarify' his role - Curbishley felt his position had become untenable.

Curbishley was told to cut costs over the summer, but he did not realise the extent of the club's financial problems until they began selling players without his consent.

Freddie Ljungberg's astronomical contract was paid up, John Pantsil and Bobby Zamora were sold to Fulham and Ferdinand signed for Sunderland last week.

Central defender Matthew Upson, who has forced his way back into the England squad, was considered by Arsenal but Arsene Wenger signed a cheaper option in Mikael Silvestre.

West Ham have subsequently confirmed that reserve team coach Kevin Keen will step in as Caretaker Manager until a new boss is appointed. First team coaches Mervyn Day and Glynn Snodin are believed to have left the club with Curbishley.