A few days from now, in early April, Mark Cavendish is due to become a father for the first time. As he awaits the arrival of his baby daughter, and during a brief lull in this year of supreme ambition for the world champion cyclist, Cavendish leans across a shiny white table and describes his emotions and plans in raw detail. His gaze glitters fiercely and his voice thickens with feeling.

"It's already changed me," Cavendish says of the imminent birth. "It's made me more motivated than ever. A lot of people who have kids have said it'll soften me and I'll take fewer risks on the road. But, for me, it's the opposite. I want to provide the best possible life for my daughter. I want her to be so proud of me. You know, I never rode just for myself. I did it for my team as well. But this feels different. This feels like I'm riding my heart out for her."

Cavendish pauses in mid-flow, as if to check that his gravelly words are understood less as a product of sentimentality than a statement of intent. He needs to be ferocious this summer. His defence of the green jersey in the Tour de France and his pursuit of an Olympic gold medal are wrapped around each other – with almost suffocating intensity. The Tour's final sprint down the Champs-Élysées is followed six days later by the road race at London 2012. But Cavendish's conviction that he can achieve both goals is bolstered by his passion for fatherhood.

"The two go together," he says simply. "I become a dad and then, with even more incentive to win, I'm harder to beat. I feel that right here."

Cavendish thumps his heart; before laughing at the fervour with which he lives his life. "I know every dad probably says this," Cavendish murmurs, more shyly, "but I don't think there's going to be a baby more loved than this one. Her room's ready. Her stuff's ready. Her mum's ready. I'm more than ready. She's due on 5 April and I've got three-and-a-half weeks at home so it works out perfect. I'm going to be living with my three princesses. They'll all get away with murder but it's going to be amazing."

Apart from his daughter and partner, Peta Todd, the third princess in Cavendish's royal trio is a small dog called Nala. "You know The Lion King?" Cavendish barks. "My Nala is a hardcore puppy. She's so greedy that the other week I watched her swallow a mouse whole. She thinks she's a snake. So we've got Peta, Nala and the smallest princess."

Cavendish makes it sound as if, in deepest Essex, he's going to live in a pink castle with his beautiful and omnipotent princesses. "You wouldn't believe me at home," he says. "Since Peta has been pregnant I've been so protective. And I've hardly stopped talking to the baby. I keep telling her I'm going to do good by her. That tells me why, more than ever, I'll get the best out of myself."

Even by Cavendish's extreme standards this has been a tumultuous start to the year. So much has unfolded over the past three months that we need to do two separate interviews to cram in half of everything that has already happened in 2012. In his debut season for Sky, Cavendish has racked up numerous wins, lost a few, had two bad crashes, suffered with illness and a bad back and vomited copiously.

"Yeah, it's been busy," he says with a cackle. "Since I met you last time I've had lunch with the Queen. It was just 10 of us. The Queen, the Duke of Edinburgh, me, and seven cool people.Some were authors and historians. I couldn't believe how informal it was. The Queen and the Duke were dead normal. It was one of the most chilled out, interesting lunches I've ever had. I loved it."

Cavendish loves riding hard in a bunched sprint even more than lunching at Buckingham Palace. The grit and cunning he will need during the gruelling back-to-back demands of the Tour and the Olympics were evident last month in Belgium – over the bumpy cobbles and hard roads of Kuurne-Brussels-Kuurne. It might only be a semi-classic but this opener to the Belgian road season was simply classic Cav.

"What a race," he exclaims. "I vomited around 10 times. It's a problem I get in the big races. It's not really nerves – more the intensity of racing. It churns the acid in my stomach and I throw up. I vomited the first time 10 minutes into the race. We'd just got over the cobbles and I told CJ [Chris Sutton, his Sky team-mate] I didn't feel good. I threw up straight after that. It went on the whole race. Again and again. It's hard because, during that race, we take on board 6,000 calories. Each time I ate, I vomited."

Riding and spewing, spewing and riding, Cavendish clung on. He was helped by his team-mates and, as always, Cavendish was blisteringly victorious in the final sprint. "They were incredible," he says of his team. "They rode that race like a video game. It was spectacular – the way they delivered me into position at the end. I just had to do my thing – like Copenhagen."

Cavendish "did [his] thing" to perfection in Copenhagen last September, when he became the first British man in 46 years to win the world championship road race. His GB team-mates, led by David Millar and Bradley Wiggins, rode a strategically masterful race as they set up Cavendish for his venomous finish. Even when his rivals looked to have pinned him to the kerb, Cavendish saw a previously invisible opening through which he could burst.

"I just knew the gap was there," Cavendish says as he tries to explain the geometric precision with which he sees the dazzling spaces for his explosive finishes. " It's an opening that's only visible in my head. I don't really calculate it and there no sense of thought involved. There's no emotion. I just see the gap and, instinctively, go for it."

Cavendish, especially the second time we talk, is in an ebullient mood. He slips effortlessly from that monumental feat to a hard-working plug for his new sponsors. "It feels like I've got a winning ritual with Head & Shoulders," he says smoothly.

It's hard not to laugh. "I am good, aren't I?" Cav quips.

Cavendish is bullish about his prospects of winning the devilishly difficult Olympic road race. "I think there's a very real possibility," he says evenly. "The Olympic Games are in London and we've got the strongest team Britain has ever had. This is probably the strongest road team any nation has had. And we've got the fastest sprinter in the world [Cavendish himself]."

Yet, over a much more demanding course than Copenhagen, and with the team obliged to feature only five riders, rather than the eight who plotted victory in the worlds, Cavendish will be tested. The fact that he'll have less than a week to recover from the Tour adds to his task – which must be the hardest he has faced.

"Maybe that's not necessarily the case," Cavendish counters. "With the strength of our team we have a real good chance. Of course it's not like running a 100m sprint in eight different lanes. This is a 250km bike ride with so many variables. Two hundred riders are jostling for the same position. Those massive variables make it hard."

Cavendish, for all his brilliance as a winner of 20 stages on the Tour de France, is not invulnerable. In a sport as brutal as cycling – where adversity, misfortune and skulduggery lurk – the "variables" are also freighted with searing competition. His failure earlier this month to finish Milan-San Remo, which in our first interview he extolled as one of his targets for 2012, was accentuated by the disappointment of not winning the Gent-Wevelgem classic last Sunday. As in Milan-San Remo, his team could not keep pace and deliver him into position for the sprint. He had also fallen heavily last Wednesday – when a rider from the Russian team Katusha threw a bottle into his spokes.

Even before that senseless act, Cavendish had lamented to me that, "I've noticed a lack of respect in the peleton. The old guys have a chip of their shoulder and the young guys have such pressure to get a result. There's no gentlemanly respect anymore."

Cavendish will now prepare for the races that matter most – the Tour and the Olympics. "London is definitely not straightforward like Copenhagen where we could control the bunch. We've got less riders and the recovery time between climbing Box Hill nine times is short. Going up Box Hill once and even twice is not going to feel much of a climb. After four or five times it'll bite. Doing it the ninth time, it's going to feel like a mountain. But I've climbed mountains before. It's a good course for us."

Yet he will miss the injured Millar whose doping past also makes him ineligible for selection. Wiggins' prime Olympic aim is the time-trial a few days later. It's hard to believe that, inbetween his tilt at winning the Tour and the time-trial, Wiggins will have much energy to ride hard for Cavendish.

"I've spoken to Brad," Cavendish says. "He wants to do everything for the road race as well. We're in this together."

The most outrageous dream for British cycling, even before the Olympics, is that Wiggins and Cavendish pull off a seemingly impossible feat of winning the yellow and green jerseys at the Tour de France.

"It's very possible," Cavendish says. "We've got the team and riders to make that goal. We've got guys who can ride tough all day, guys who can lead out, guys who can ride in the mountains. Brad's going great and his form is exceptional."

Wiggins' achievement in winning Paris-Nice this month bookends Cavendish's world championship – for they became the first British riders to match two landmark Tom Simpson victories. Simpson won Paris-Nice in 1967 – two years after his world champion road race triumph.

"Tom Simpson was a big spur for us," Cavendish says, explaining how Rod Ellingworth, the race coach for Team Sky, used Simpson to galvanise their world championship bid. "Rod was incredible. At our first camp he didn't say anything at first. Rod just showed us a video of Tom Simpson winning the worlds in 1965 and then he unveiled a framed jersey. It belonged to Tommy Simpson. The room was deadly quiet and Rod said, 'Right, we're bringing this back to Great Britain.' It bought me out in goosebumps. We've now got the bigger picture of the Olympics – and that exact same passion."

As the sun dips and fades on an afternoon which finally feels like winter has given into spring, Cavendish looks out of a window in Essex and towards the east end of London and the site of this summer's Olympics. "I'm 100% confident I'm going to be flying the rest of the year," he says huskily. "The baby, the Tour, the Olympic road race. That's some hat-trick, isn't it?"