Nicola Adams: As long as she has her Frosties, she will keep making history

It could read like the opening scene of a 1950s film noir. It's dark, a cold, dirty rain drizzles across London's docks in a corner of the city, like so many dark corners of so many cities, where an outsider can never feel at ease…but that won't work because Nicola Adams is waiting in this particular dark corner of the capital and it seems likely that she has not stopped smiling since the moment, four months ago, when she had her left arm raised towards the same east London skyline and was anointed Olympic champion.

Boxing has history in the movie world and Adams's story, which reached its high point not far from this dour waterfront, makes for a new contender; this one, though, the story of a somebody – and a happy one too. Adams is a smiler. Her eyes smile. Watch when her turn comes sometime on Sunday night – back in Docklands again, as it happens – during Sports Personality of the Year. There is an infectious delight there. Britain will smile with her once again as it did in August when she made history on her own, the first woman to win an Olympic boxing gold.

The medal is in her pocket when we meet. She, it and Anthony Joshua, another London gold medallist, are in an east London gym, brightly lit against the outside gloom and buzzing with use and excitement, to support an organisation called Fight for Peace, a charity set up in Brazil by a Briton, Luke Dowdney. Now it is using the same formula to try and make a difference in an area of London too often left unloved.

Adams has been to Rio to see where it began. She flew there with the Prime Minister. This is the strange new world in which Adams finds herself because of her sporting exploits: living, it seems at times, the life of a movie star – premieres, chat shows, celebrity. It is a long way from her previous existence when she took work as an extra on Coronation Street to help make ends meet.

"Have you seen City of God?" she asks. Now that is a dark film, a brilliant telling of life on the wrong side of the tracks in Brazil that is both brutal and life-affirming. In some parts of Rio it is like that. The stuff [Fight for Peace] are doing for the kids, getting them off the streets, using sport to do that, is fantastic and it's fantastic it has come over here. There has been trouble here with knife crime. Education and sport – combine the two together and it gives kids and teenagers something to do."

The main hall of the gym is packed with teenagers, all wearing white T-shirts branded with the words "Fight for Peace". A couple are in the ring, being put through their paces by two trainers. "Boxing has done everything for me," says Adams. "It gives you discipline, team-building. It's a little family. You see these people every day, you build a bond with them. It's a nice thing to have, a home from home."

The charity chose London as its British home because of the problem of violent crime among young people in the capital. It settled on Newham, one of the Olympic boroughs. The gym is a handful of stops on the Docklands Light Railway from the ExCel Centre, where Adams won her Olympic gold and where she will bookend her remarkable year on Sunday night.

Now 30, Adams has boxed since the age of 12. She has become used to breaking boundaries; for the last five years she has been making history, some of it of the footnote variety – the first English woman to win a medal in a major tournament at the 2007 European championships – some of it most definitely not. Over five days in August she fought her way into every future Olympic history book.

"Before the first fight I couldn't sleep," she recalls. "I was nervous – I'm always nervous before competitions. I wanted to perform so much. I was lying in bed thinking about it. I couldn't switch off."

The time between bouts did not pass quickly. Her first fight was on a Sunday afternoon, the next the following day, then a day off before returning for a semi-final against India's Mary Kom, five times world champion. "I played computer games or wandered around Westfield shopping centre – I went to see Ted at the cinema. Anything to try and switch off and relax. I would put a hat on to try and not get noticed but as the week went on it was harder and harder to keep myself disguised."

Before the semi-final another problem arose. Like many sports people Adams has her thing, the one piece of the jigsaw that is not fitted by training, ability, desire and the rest of the long list needed to be successful. "I always have Frosties before I box," she says. On the eve of her semi-final the supply ran dry. "I was sending my coaches around [Westfield] to get me some more Frosties. I was like 'I can't box without them'. I can't do it, really."

The coaches did their search-and-rescue job and then Adams did hers to set up a final against Ren Cancan, the Chinese fighter who had beaten her in the world championships. Watching those four two-minute rounds again is to relive a composed, commanding performance by Adams. The flyweight has magically quick feet and danced around the ring outpointing a high-class opponent. She won the first three rounds and when the referee called the fighters together after the fourth there was no doubt about the outcome.

"I was so happy. Ren Cancan had beaten me in two world finals. I realised that none of that mattered any more. I've got that Olympic gold. It felt like a fairytale ending. It's been fantastic. My life has totally, totally changed. All I went in there thinking was I want to win a gold medal. I didn't realise how the country was going to embrace me, take me to their hearts. I am still getting messages on Twitter and Facebook saying you've inspired me to take up sport or boxing. That's fantastic."

She lists her post-Games whirlwind. "I've been to Rio with the Prime Minister, met the Queen, went to the Pride of Britain, the Mobos, the premier of Twilight, I've done Eight out of 10 Cats, Alan Carr. I can't really believe it. At the Games you are in this bubble, it's difficult to realise what's going on outside. You go from the gym to the village to the boxing. It's not until you win and the bubble pops and it all pours in."

She is back at the ExCel on Sunday after a belated holiday in Mexico, then back in the ring after Christmas. "I want to go to Rio," she says. "First the Commonwealths and the chance to make another first there. Then hopefully go to Rio and become a double Olympic champion. In boxing we have never had one before – that is another first I would like to get under my belt. This was just the start of what's for me. Now it's the start of another dream."

Boxing clever: A career of firsts

1994 Starts boxing at the age of 12, a year later she wins her first bout.

2001 Becomes the first female boxer to represent England, and wins an international against Ireland.

2007 Wins silver at the European Championships, becoming the first ever English woman to win a medal at a major boxing tournament.

2012 In London, becomes the first woman to win an Olympic Gold medal.

2012 Also becomes the first woman to receive an award from the Boxing Writers' Club of Great Britain.