RONNIE O'Sullivan could face expulsion from the Embassy World Championship after an alleged attack on a snooker official at Sheffield yesterday.

O'Sullivan is due to start his quarter final against John Higgins or Alan McManus tomorrow, but may well be disqualified for an unprovoked assault on assistant press officer Mike Ganley.

If the decision is made to expel the 20 year old from Chigwell in Essex it will be unprecedented in the sport's history.

Alex Higgins was banned from the 1990-91 campaign for punching one of Ganley's predecessors, Colin Randle, in the stomach after his first round exit at the 1990 event.

But his punishment took into account an incident during an earlier tournament when he threatened to have fellow Ulsterman Dennis Taylor shot.

Yesterday's flashpoint occurred after a friend of O Sullivan entered the press room to watch the day's action on the television monitors. Ganley requested to the world number three that his friend, a familiar figure on the circuit known as Del Boy, should leave.

As the trio were making their way out of the room backstage at the Crucible, O'Sullivan is alleged to have struck out at Ganley, son of leading referee Len Ganley.

The bespectacled official was unavailable for comment as was O'Sullivan who left to return to his Sheffield hotel.

It is the second time at the championship O'Sullivan has landed himself in trouble. He is already facing likely disciplinary action for a verbal assault on French Canadian Alain Robidoux.

O'Sullivan was angered by Robidoux's decision to call him "disrespectful" for playing left handed during their first round game last weekend.

O'Sullivan, whose dad, Ronnie senior, is serving life for murder, hit back saying: "I didn't give him any respect because he didn't deserve any. I am better playing left handed than he is right handed."

For those comments he could face a small fine, but for this latest incident he now faces the ultimate disgrace.

A statement was later issued by the game's ruling body saying: "An incident has been reported to Ann Yates, tournament director of the World Professional Billiards and Snooker Association, concerning an incident involving Ronnie O'Sullivan and a WPBSA official.

"A report has been made on the incident and pending further consideration of this, the WPBSA has no further comment to make at this time."

It is expected a decision will be made today when all the facts surrounding the case have been heard. Embassy consultant Peter Dyke refused to speculate on the outcome saying: "We hope the outcome will be in the best interests of everyone concerned."