In the first instalment of her new Telegraph column ‘Sport and Social’, Pippa Middleton picks up her boxing gloves.

The air was heavy and sweet with the sweat of adrenalin-fuelled bodies. Every so often the dimly lit room seemed to shudder as a Tube rattled through far below. I stood there a little uncertainly, well aware that in my slinky workout attire I was inappropriately dressed. The 20 or so men and women around me knew better, opting for loose-fitting T-shirts or wife-beater vests.

This dingy location – a former air-raid shelter – under a railway arch was a club, but not the sort I was familiar with: no VIP areas here. As for Happy Hour… forget it. Skipping ropes, punch bags and an array of pungent-smelling gloves were the props. The Fitzroy Lodge Amateur Boxing Club in Lambeth, south London, is an altogether more serious establishment, the place where the famously intense actor, Daniel Day-Lewis, prepared for his role in the 1997 film The Boxer.

That was the first of what have become regular visits over the past year. Boxing had been nowhere on my list of New Sports To Try until I signed up for a cross-country ski race in Sweden in 2012 and began training in earnest to improve the strength in my arms for the rigorous 90km of double-poling. A favourite childhood book of mine, The Power of One by Bryce Courtenay, is about a young boy called Peekay who sets his heart on becoming welterweight champion of the world. Other than that, I associated boxing with scenes of blood, drugs and violence, my vision influenced by the stars of brutish movies such as Sylvester Stallone in Rocky or a drug-addicted Christian Bale in The Fighter.

However, a fitness fanatic friend urged me to give boxing a go, if only for the sake of building my biceps for my Scandi skiing. And to be honest it was the prospect of a more svelte silhouette that persuaded me. That and the Oscar-winning film Million Dollar Baby, for which actress Hilary Swank transformed her body as she trained for the role of wannabe champion boxer, her amazing toned and tuned physique captured by photographer Norman Jean Roy in an iconic portrait for Vanity Fair.

The basics of the boxing classes I attend at Fitzroy Lodge are the same week in, week out, rugged and ruthless: a five-minute skipping warm-up, not the school-playground-gallopy-type, but a boxer’s skip, requiring speed and agility. The aim is to barely lift your feet off the ground, as if you’re just tapping each foot over the rope, requiring balance and co-ordination. For weeks I was a mess of tangled rope at the back of the hall, desperate to achieve lightness of foot and relaxed, rhythmic skipping.

For the circuits we pair up and take it in turns to hammer sand bags, the frustration of the working day eradicated in a few short bursts of intense exercise. It’s a remedy for the mind, body and soul, both exhilarating and exhausting. I find myself lost in concentration, oblivious to the seedy surroundings, throwing punches, swinging my hips, pivoting back and forth while aiming to maintain the correct weight exchange on my feet.

Our coach is unrelentingly tough on us all during our pad work in the ring where we jab, hook, punch and attempt an uppercut and duck. We try, but fail to impress. There’s no pilates posing or pampering with cold towels and mist sprays at this gym. We swap in and out continually for two-minute sessions, and I swear I’m seeing stars and hanging back against the ropes as the rounds progress, praying for the bell to ring. But then there’s the gruelling warm-down; 20 squat-thrusts, 20 press-ups, 20 squat-thrust-jumps and 20 star jumps, repeated again and again. It’s an hour and a half of pure but pleasing agony and by the end I’m broken, worn out and worn down, but I leave on a high, hiding the sweat patches under my hoodie, delighted to have found muscles and fitness I never knew existed.

One of the biggest pluses of boxing for women – given a tremendous boost by Nicola Adams’s Olympic gold last year – is undoubtedly the prospect of a better body and the chance to crunch up to 600 calories an hour toning up arms, bums and tums, and banishing bingo wings, back fat and booze blubber. But boxing’s appeal for me is broader than that. Many boxing clubs have a community role and Fitzroy Lodge is no glam-gig, but a thriving non-profit-making charitable establishment: shabby outside and in, but a hub that engenders discipline, self-control and motivation in all who attend.

The club was founded more than 100 years ago by a local doctor who wanted to improve the lives of underprivileged children. Today it attracts boxers from all over London. Mark Reigate, the ex-club boxer who runs it, is a big-hearted man with a huge smile. He embraces men and women from every age group and all walks of life and professions: lawyers, accountants, former rugby players, army boys, builders and, dare I say it, bankers; be it for serious boxing training, recreational boxers, keep-fitters like me, love-handled couples before their wedding day, youth groups and children as young as nine. Everyone is welcomed and treated the same.

It’s not only a form of fitness – an escape from school, work and nagging loved ones – but also, for many troubled youngsters from the streets and broken families, a place to learn, focus and have a purpose, just as Peekay learnt to “think with his head and then with his heart”.

Next Saturday, I’ll be present at the Boodles Boxing Ball, a fundraising event in which 12 young guys who’ve been trained to box over nine months at Fitzroy Lodge will fight each other in front of an audience of 1,000. It’s a great cause.

I’ve also been working with The Sported Foundation, a charity dedicated to improving the lives of disadvantaged young people through sport. It provides funding and business support to community and grassroots projects across the country, including Fitzroy Lodge.

On one recent visit, as I paused to catch my breath after pummelling the punch bags, I got talking to a young Jamaican, who shares my love of the place. “Boxing and my coaches’ support really took me away from street life,” he told me. “The Lodge is my second home where I learned the things they couldn’t teach me at school – honour, respect, courage and to do the right thing”. Speaking of our mutual coach, he said: “He’s like a father figure… I want to prove to him that I’m a good guy, and having admiration from him means everything to me”.

While I may have acquired muscle tone and a crushed ego from my workouts, boxing has given this boy and many others – just like the Peekay of my imagination – real ambition, a sense of being part of a family other than their own, and a purpose in life. It’s made me look at this sport with fresh and approving eyes.

Pippa’s Picks : five things to try …

1. Top read: The Power of One by Bryce Courtenay. It’s inspiring, emotional and moving.

2. Coconut water: a great thirst quencher after exercise. Try VitaCoco or Cocofina.

3. The plank: a Pilates exercise for flat, surfboard tummies. Do daily, working up to a two-minute hold.

4. Kubbs: a Swedish wooden garden game. It’s similar to skittles, but more violent.

5. Telegraph Weekend’s General Knowledge Crossword, page 17. I’m completely obsessed with it.

Pippa Middleton will be writing fortnightly for Telegraph Weekend, out on Saturdays.

When I close my eyes and think about school sports, I envisage myself on the hockey pitch, stick in hand, a luminous gumshield locked on to my chops and a bandana across my forehead. (Bandanas were all the rage back then.) Boys are watching. I can also hear the booming voice of Mr Markham, our fierce but undeniably fanciable coach, urging us all on. The other Mr M in my life (father and also coach) is on the sidelines, and I’m desperate to impress him most of all. My knees and knuckles are badly grazed from the astroturf, my shins are battered and bruised from the bully-offs. But my focus is on winning and making sure that my hair — fashioned into a slick Sporty Spice ‘up do’ — is just right. Did I mention the boys watching?

Hockey was my favourite: I was captain and proud. But all good things come to an end, and hockey ended with the Christmas term. The following term, we had to play netball. People say netball is like basketball with all the fun bits taken out. I’d tend to agree. You can’t run with the ball and only two members of the team can shoot. You spend most of the time playing a complex version of piggy-in-the-middle, except the piggies are a pack of vicious girls. My petite physique enabled me to nip and tuck my way past the bigger-chested girls. Elbows always helped; as did the derriere for defence (my ‘chest’ hadn’t developed back then) and a bit of shoulder-barging here or there. It was brutal, but turns out to have been very useful practice for handling the media in later life.

Some of my fondest memories are of school sports day. I recall the odd personal mishap: forgetting the baton in the 4 x 100m relay race, dropping the shot put on my foot and treading on my brother with a spiked running shoe are three that spring to mind. There was always a stray dog that would defecate in the long-jump pit and the high-jump mat was always soaking from either rain or tears. Best of all was the mothers’ and fathers’ race — a fiercely competitive event which brought about more injuries per contestant than any other.

On the subject of mothers, I must touch on cross-country — one of the most gruelling compulsory school activities, along with public speaking. Unlike many of my friends who ‘suddenly got the flu’, we Middleton girls were always at the starting line — albeit reluctantly — fuelled by Lucozade tablets and bananas. Rain was inevitable and we’d get caked in mud from head to toe, in our tiny athletic shorts, white Aertex and all.

To really rub our faces in it, the teachers would wear fleeces, gilets and waterproofs. I was born more of a long-distance runner — something to do with my endurance and sturdy ‘piano legs’. On one occasion I recall being in second place, and as I passed my mother on the perimeter, I was feeling quite proud of myself until she called out, ‘Run faster, Pippa, run faster!’ What did she think I was trying to do?

The real horror — far worse than netball or cross-country — was the swimming gala. Everyone had to walk around sheepishly in tight Speedo bathing suits and streamlined swimming caps. And with swimming, of course, came the nightmare of the pool changing rooms: those awkward communal showers, the lingering scent of chlorine and adolescent body odour.

But all the hot weather of the last few months brings back cheerier memories of playing rounders. When batting, I always took pleasure in hitting the ball into the stinging nettles. Fielding was usually boring, unless I was bowling or at 3rd base, where all the action is.

On Saturday afternoons, after rounders matches, I’d go off to watch my brother playing cricket. I recall one match when he got the yips trying to bowl spin, and kept being no-balled. He gave away so many runs that his team eventually lost the match. I was so embarrassed that, rather than rallying to his support, I hid behind the scoreboard and missed out on match tea. Family, eh?