Troubled Australian snooker star Quinten Hann has pulled out of the Malta Cup.

Hann, set to stand trial in London later this month on four counts - including two of sexual assault - was due to face world champion Ronnie O'Sullivan in the first round on Wednesday.

But the 27-year-old has withdrawn without submitting a formal reason, giving O'Sullivan a walkover.

Hann, who is pleading not guilty to all criminal charges, has had a chequered career which has been more notable for controversy than success on the table.

Last season, he had to be separated from Andy Hicks after losing to him in their ill-tempered first round match at the Embassy World Championship. He then offered to fight Hicks in the ring to sort out their differences.

Although Hicks passed, Mark King did fight Hann in a licensed contest at Bethnal Green last summer where the Melbourne cueman won on points.

In the past, he has been renowned for smashing into the reds in frustration and has even conceded frames when he has been ahead.

Hann, currently ranked 18th in the world, once played in a tournament without shoes after breaking his ankle during a parachute jump. He missed three events early on in his career because of a bike accident.

The former world 8-ball pool champion joined the top 16 three seasons ago but was relegated after last year's world championship, despite moving to London to live and practise full time.

Last Friday, Hann beat Darren Morgan 5-2 to qualify for the final stages of the China Open which will be held in Beijing in March.