There were disgraceful scenes at St Andrew's after Birmingham City failed in their battle to stay in the Premier League.

A mob of angry fans vented their fury, despite Blues winning their last match of the season, by invading the pitch and tearing down the goalposts.

Blues may have lost more than their Premier League status when they dropped out of the top flight despite a surreal 4-1 hammering of Blackburn Rovers.

Fulham's win at Portsmouth meant Birmingham's victory was not enough and although most of the afternoon passed in a carnival atmosphere, things turned nasty shortly before the final whistle when a handful of supporters turned their anger on the club's board.

As a result the £60 million bill for relegation may be compounded by boardroom instability with owners David Sullivan and David Gold threatening to end their 15-year tenure at the club after they were verbally abused and chants of 'Sack the board' rang round St Andrew's.

Speaking afterwards Sullivan, whose children David Jnr and Jack were reduced to tears by the protests, said he wants to leave Birmingham while Gold vowed to stand down as chairman if it becomes clear the majority of supporters are against the current regime.

"These people know nothing about business and nothing about football," Sullivan roared. "I have had enough, I do not want to be here next season.

"All these people who want a share in it can buy it like what happened to Ebbsfleet [a reference to the takeover of non-league outfit Ebbsfleet United by fans' community website MyFootballClub].

"This is a message to David Gold - please buy me out, David. There are five or six clubs who welcome me with open arms. It is time to move to another club."

A visibly shaken David Gold said the fans' abuse had been the worst he had experienced at the club. "You could see the hate in the eyes of the people sat in front of us. It was a venomous verbal attack," he said.

The painful irony for Birmingham is that while some supporters vilified the club's management, others cheered their team to the highest win of the season with goals from David Murphy, Fabrice Muamba and two from Cameron Jerome.