In any conversation with Ronnie O'Sullivan, it is striking how often he refers to his father. In response to a question about life after snooker: “I want to bring my son up to be the next Wimbledon champion. Along with my father's help, of course, because that is what he done with me. I believe that champions are made, not born. I have to give my dad the credit because he made me what I am. Listen to Tiger Woods talking about his dad. It's like that with my dad: he gave me everything.”

In response to a question about the China Open, where he went out in the first round after a frantic week of commercial activity with Chinese sponsors: “I was upset with myself because everything I did was the exact opposite of what my dad had taught me. I was there to socialise and network rather than win a snooker tournament. Dad instilled in me how to be a winner. He would be embarrassed to know how unprofessional my approach was in China.” And so it goes on.

Despite spending the past 16 years in prison for murder, it is evident that Ronnie O'Sullivan Sr is the gravitational centre of his son's universe, the man who provides orientation and direction, the subconscious presence in his every waking thought.

As the clock ticks down to his father's release, O'Sullivan, 32, who will attempt to win his third world crown at the 888.com World Championship, which starts in Sheffield today, is wavering between excitement and chronic apprehension.

“I think about the day of his release all the time,” he says. “I have thought about it every hour of every day since he was locked up. It is quite frightening, as it happens. Sometimes I get worried because he might be surprised at how negative I can get when things aren't going well. We speak every four or five days, but that is not the same as knowing each other on the outside. His release date is 2010, when he is eligible for parole.

“The really scary thing about him is how positive he is. In there he is liked because he keeps everyone's spirits up. I have met numerous people when I am on a visit telling me they want Dad back in their wing because he keeps everyone buzzing. They say, ‘Since he has gone, everything has gone downhill.' That is the biggest compliment you could give to anyone. Because there are people in there who are incredibly strong but who just can't take it.”

O'Sullivan Sr, the owner of a string of sex shops, was convicted of murder on September 21, 1992, for the knifing of Bruce Bryan, a driver to Charlie Kray, the elder brother of the Kray twins. Accounts vary, but what is certain is that the stabbing took place after an argument in a Chelsea nightclub. Summing up, the judge implied that the attack was racially motivated, a contention that was overturned in a sentence review in 2003.

“The only things that can keep you going on the inside are humour, patter and character,” he says. “Somehow Dad has the ability to stay on top, regardless of what is happening. You know, after nine years in jail he said to me, ‘It's all downhill from here.' I said, ‘Dad, how on earth can you say that? You have another decade to go.' But that is what he is like, just incredibly strong. Having someone like him on my side is like this huge security blanket. He makes me feel safe and lifts me when I am feeling down.”

O'Sullivan has had a solid season, with victory in the UK Championship in December the high point. But no season would be complete without an incident and in March at the China Open, O'Sullivan was on the front pages of the tabloids again for making lewd comments after losing to Marco Fu in his opening match.

“I am sorry it happened, it wasn't intentional,” he says. “It was a joke between me and a friend. It wasn't loud enough for anybody to hear it had it not been for the microphones, which I did not realise were on. It is so embarrassing for me to look at it on the internet, not just because of the comments but because I giggled through the interview. I am not making excuses, but my mind was not on snooker that week and I apologise if anyone has taken offence.”

Despite O'Sullivan's maverick behaviour in China, he starts the World Championship as the bookies' favourite and claims to be enjoying his snooker more than at any time since he was a teenager. “I have made some technical changes to my game and it has made me feel so much more comfortable over the ball,” he says. “I am practising with more passion for the sport than for a long time. And there are far fewer distractions than before.”

I ask if he is off the booze, something that threatened to wreck his career when he checked into the Priory in 2000, the consequence, perhaps, of the complex feelings of anxiety and guilt that have plagued him since the imprisonment of his father. “I still have a drink now and then, I am not going to lie,” he says. “I have a glass of wine. It's not a problem. I don't sit at home thinking, 'I need a drink or I want to go out and party.'” When was the last time you went on a bender? “About two or three weeks before I went to the China Open. But, even then, I was only out from 10pm to 2 in the morning. Before when I went on a bender it was for two or three days.”

Can you honestly say that the drinking is under control? “The word control means you are having to force yourself to stop at a certain time. I don't look at it like that. It's more a lifestyle thing. My lifestyle doesn't give me the time or opportunity to do it much.”

You mean the running? “Exactly. I do between 30 and 50 miles a week when I am at home and I know that if I were to go out drinking I would have to give up the running. And that ain't going to happen. Running is the main staple of my life now, it is the thing that holds me together.”

Why has it become so important to you? “It is, like, totally cleansing, as if you are putting your body through some really healthy pain. It takes a mile before you can warm up and then all of a sudden your body is relaxed, your hips are moving, your legs are ticking over and it is more of a rhythm thing then. It is the most important thing in my life. If there was a choice between snooker and running, it might sound disrespectful, but I would choose running every time.

“Throughout this season a friend from my local running club has e-mailed clubs near where the tournaments are so I have a chance to keep my running up at competitions.

“It has been fantastic getting to be out in the fresh air, getting to know new people rather than hanging around at the venues talking about snooker. I am going to do the same at Sheffield this year, get out there and do some really tough workouts on the outskirts of the city. It will be heaven.”

For more information on the World Championships, go to 888snooker.com

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