Ronnie O'Sullivan has raised the familiar red flag of a retirement threat after accusing World Snooker chairman Barry Hearn of leading an institution that has bullied him.

A stunning verbal attack from O'Sullivan came on the second day of the Betfred World Championship.

It was triggered by the five-time Crucible champion being reminded that Hearn said his clipped answers and eccentric behaviour in recent media interviews had become "embarrassing".

The 41-year-old cueman turned the tables on Hearn and his board, stating he had been left distressed by a letter from disciplinary chiefs after he criticised referee Terry Camilleri and swore at a press photographer during January's Masters.

O'Sullivan says he had been pushed over the edge by the reaction from World Snooker, having been incensed by previous disciplinary cases opened against him.

O'Sullivan progressed with a win over Wallsend's Gary Wilson (Getty)

"I phoned Barry up four weeks ago and I said, 'Look Barry, I'm done with all you and your board of people'," O'Sullivan said.

"And I've got a very good friend of mine who said, 'Just let my lawyers deal with it'. I won't get involved with it because I'm not being bullied, I'm not having people doing that to me ever again.

"I like Barry but I'm not being intimidated or bullied any more."

He added: "I've given 25 years of service to this game and I think I've given enough. Drop me out, I don't need you, you probably don't need me."

Hearn has fallen out with one of his star players (Getty) (Getty Images)

O'Sullivan has threatened to quit snooker many times over his career.

The former world number one's latest comments were explosive, yet it is worth remembering that although O'Sullivan was asked to explain his Masters remarks, he avoided punishment.

Hearn declined to respond to O'Sullivan on Sunday evening.

The crowd favourite made the accusations after launching his 25th Crucible campaign with a 10-7 win over Wallsend's Gary Wilson, whose debut in Sheffield won him new admirers.

This is not the first time O'Sullivan has threatened to retire (Getty)

O'Sullivan said the strain upon him from receiving the disciplinary letter had ruined his season since the Masters, and he had become reluctant to engage with media out of concern for any comments triggering more action.

"I've had it for five, six, seven years, and I'm just done with it," O'Sullivan added.

"It's not that important. I could go and do Big Brother, I could go and do I'm A Celebrity... Get Me Out Of Here, I could have a great life doing other stuff. This is something I do for love, but I'm not going to do it and have people trying to intimidate me and bully me."

Could O'Sullivan be heading to the celebrity jungle? (Rex)

Away from the controversy, Monday sees former world champions Stuart Bingham and Peter Ebdon resume their first-round battle, with Bingham 5-4 ahead overnight.

Shaun Murphy will look to convert a 6-3 cushion over Chinese 17-year-old Yan Bingtao into a trouble-free victory, with O'Sullivan awaiting the winner of that match.