Smash hit: Andy Murray swings into London

During a press conference in Paris, Murray answers questions readily enough but seems inaccessible, avoiding eye contact with journalists. Occasionally he reaches in his pocket to unwrap a sweet - the soft, chewy variety, so not a Murray mint - and although he's polite, there's a distinct lack of flow to the proceedings. However, when we meet afterwards, he relaxes, flashes a terrific smile and is more forthcoming.

No doubt he was annoyed during the conference by questions relating to his progress in Grand Slam tournaments (the Australian Open, the French Open, Wimbledon and the US Open). Unlike Nadal, Federer and Djokovic, 22-year-old Murray has yet to win one. And so the pressure, both self- and externally imposed, continues to mount, not helped by the age limit he places on his career, 'between 28 and 33 years old'.

Surely, it must feel like a noose but he claims not. 'There's no rush for me to do things,' he says. 'I just try to relax and not think about it too much. A player's point of view is a lot different to the expectations of the media. They feel that it's been so long because they want it to happen so quickly. Sport doesn't always happen like that.'

By his own admission, he revels in 'a quite complicated game. I don't play like any of the other guys on the tour. It takes time to mature and understand the right way to win matches all the time.' He's pleased with his achievements this year, which saw him reach the semi-finals at Wimbledon and the quarter finals on his least favourite surface, clay, at Roland Garros in the French Open.

Since he turned professional in 2005, Murray has had a thorny relationship with the public. In terms of tennis, he excited people desperate for another Fred Perry, or a more successful Tim Henman. But he was labelled as surly and charmless, thanks to his monosyllabic post-match interviews and perceived impatience with the crowd on court. Defending himself, he says, 'When I played Wimbledon the first time, I was only 18. I was ranked 350 in the world and was used to playing in front of ten people.'

Suddenly he was playing on Centre Court, doing live TV interviews and being judged by 11 million people. 'They start asking what you're like as a person; they question your tennis. You get a bit defensive.' Then there was an outburst of swearing at an umpire in Glasgow, frequent McEnroeesque explosions on court, and the World Cup misquote that led to a media storm.

Murray's deep-seated wariness isn't helped by interest in his life story. Both he and his brother were at Dunblane Primary School in Perthshire on the day in 1996 when Thomas Hamilton, an unemployed former shopkeeper and Scout leader, shot and killed 16 schoolchildren and a teacher, before committing suicide by turning the gun on himself.

The Murray boys survived because they were in another part of the school. More chilling still is the fact that they knew Hamilton, having attended his youth camps, and their mother had also given him lifts in her car. For the record, Murray has said, 'I was too young to understand the magnitude of it,' while his mother has described waiting outside with the other mothers as 'the worst day' of her life.

(Right) Andy with his older brother and doubles partner Jamie at the Madrid Masters tournament in 2008

Now, though, the subject is off limits so one can only imagine the effect it had on him. He and his brother Jamie were coached from the age of five by their mother, a former Scottish tennis champion. But Judy moved out of the family home in 1996 when she separated from the boys' father Willie, a retail manager. They were a sports-obsessed family - football, golf and squash were their other favourite pastimes.

Judy was a stage mother of the sporting variety, the type to say 'shit, shit, shit' and whack her leg with a tennis racket when they were losing. There was a certain amount of sibling rivalry: Andy still sports a crushed fingernail from the first time he beat Jamie in a tennis match and then made the mistake of teasing him about it. 'I don't think my mother ever imagined that we would both play on the main tennis tour,' says Murray. 'She made a lot of sacrifices and we have managed to pay her back with some success.'

Emotionally, it was a difficult childhood. Before his parents divorced, they fought constantly and Murray has admitted that playing tennis allowed him to be 'free from their arguments'. He was always a hugely talented player but started to take the sport more seriously when playing against Rafael Nadal in 2002. He was furious to discover that Nadal was training with Carlos Moya, the number one seed, while he only had his older brother to practise with. So he moved to Barcelona to train with Emilio Sanchez, the former number one doubles player who co-ran the Sanchez-Casal Academy. 'I was only 15 and it was tough because I had to grow up a little quicker,' says Murray.

Financially, it was a huge burden on his parents who had to find £20,000 for the fees. But the decision to leave Scotland paid off. In September 2004, Murray won the junior US Open and his success snowballed.

Although Murray is working on it, there is a lingering feeling that he lacks affection for a 'Murraymaniac' public who have renamed Wimbledon's Henman Hill Murray Mount. And in today's touchy-feely climate, that won't do. He's definitely more at home describing his tennis technique than talking about his domestic life - he lives in Surrey with his glamorous girlfriend Kim Sears, drives his Range Rover to practice at the National Tennis Centre in Roehampton, listens to Lady Gaga and Robbie Williams, plays computer games and engages in 'unfortunately, nothing too intellectual'.

He's a self-confessed 'rubbish' cook, so either Kim makes the food or they eat out - his record is 50 pieces of sushi in one sitting. He has no appetite, however, for alcohol. He is quietly bemused by Andre Agassi's experiments with crystal meth: 'No one really likes drugs in sports and he obviously made a mistake but should be forgiven.' As for himself: 'I don't drink, I don't smoke. I drank a few times in Barcelona when I was a boy but I didn't enjoy the taste. I don't like the idea of drinking to get drunk.'

In training, Andy keeps going on a diet of peanut butter bagels, pasta, chocolate-flavour protein shakes and cereals. This giant calorie consumption will keep him going for 90-minute practices on court (his 'fun' workouts with his team, playing football tennis, were a highlight of this year's Wimbledon) of which 20 minutes are spent solidly practising a serve that leaves many of his peers feeling as if they pat the ball over the net underarm by comparison.

'I am just thinking about trying to hit an ace because it's the only time in the rally where you really decide where the ball is going,' he says. The tennis practice is followed by an hour in the gym to hone his impressive physique. His team claim he can do 27 chinups in one go but, for the 11 months of the year during which he plays tennis, he loses muscle (8kg during the season) which he then spends a month building up in Miami with Bikram yoga sessions and weight-lifting. And all this in pursuit of winning which he describes as feeling like 'a weight has dropped off your shoulders; you feel really relaxed and very happy'.

The good news is that his formidable competitive instinct is focused where, ultimately, we all want it to be: 'If I had to pick one tournament that meant the most to win,' he says, 'it would have to be Wimbledon, because it's at home.'

However, during preparations for the World Tour Finals, he's clearly wholly centred on winning the next competition on the circuit, working with a team that, he tells me, consists only of his manager, trainer and physiotherapist; not a gigantic entourage, as has been previously reported. 'The press wanted to make a big story out of it,' he says. 'They made out my mum was part of the team, my brother, my girlfriend. Well, everyone's got a mum, a girlfriend or boyfriend, brothers or sisters. It's not as if they travel with me.' And with that, he heads off to nail a few more aces.

The Barclays ATP World Tour Finals run from 22 to 29 November 2009 at The O2. For tickets, visit ticketmaster.co.uk