Mark Williams in row over ‘pathetic’ treatment at Sheffield’s Crucible

He claimed his 12-year-old son Kian was prevented from visiting him in his dressing room at the Crucible to wish him good luck ahead of his opening match in the World Championship.

The 44-year-old argued that it was the latest example of what he believes to be unfair treatment of him by the sport’s governing body during his reign as world champion, an accusation World Snooker strenuously denies.

Williams, who beat qualifier Martin Gould 10-7, said: “They (World Snooker) have obviously got some kind of beef with me, but whatever it is you'll have to ask them.

"I've been having all this nonsense all season really and this morning was the last straw really. My boy tried to get in to say good luck and I couldn't get him in because I'd used my two passes.

"It's pathetic in my eyes. If you're the world champion you expect some kind of (favour). But I wasn't going to let it play on mind. It's only my opinion and they will say that nothing's wrong.”

A spokesman for World Snooker denied that Williams' son had been denied entry to the dressing room, but pointed out that the player had chosen to give his two allotted passes to his coach and his friend.

The spokesman said: "Every player in the event is allocated two backstage passes. And they can make their own decisions who to give those to. At no point were his children refused entry."

Williams, who will play either David Gilbert or Joe Perry in round two, had already expressed his displeasure with tournament organisers over what he considered to be a lack of sufficient profile in its promotional materials.

And on the eve of the event he had claimed World Snooker officials would prefer anyone but him to win the title this year, an accusation the governing body also vehemently denied.