Ronnie O’Sullivan is up against it in more ways than one in his World Snooker Championships quarter-final at The Crucible after controversy once again followed him on Tuesday.

Stuart Bingham leads the ‘Rocket’ 5-3 after the first session, although it was the 39-year-old’s behaviour with his chalk that really got everyone talking.

The Chigwell star broke snooker rules by lining up a shot with the chalk as he took a 3-2 lead in the fifth frame, but was not reprimanded by the referee.

A World Snooker spokesman has said they will now look into the incident and will ask referee Terry Camilleri for his interpretation, although there is no possibility of punishment against O’Sullivan.

Although O’Sullivan was allowed to finish his break in the fifth frame, he went on to lose the next three as Bingham opened up a two-frame lead after the first session in the quarter-final.

Pundit Ken Doherty said: “The referee is unaware, Ronnie is too but for me, that is a foul. You are not allowed to do that.

“As far as I am aware, you are not allowed to put the chalk on the table because you are using it as a tool to measure the ball.

“That is exactly what Ronnie has done. Stuart Bingham was looking at him and should really be aware. If he had more knowledge of the rules, he would have jumped up out of his chair.”