It’s half past three on Saturday afternoon and I’ve just done the toughest workout of my life. I played football for my state when I was younger and even trained at the Australian Institute of Sport with the national team, but I have never worked my body like I have in the past 90 minutes.

I have just had my first session with BoxLondon, a group set up by Scot Dearling and Naomi Ryan earlier this year in Tooting and Wandsworth to offer boxing classes for all ages and abilities.

They’re certainly qualified to do it. Dearling has trained in various martial arts and boxing since he was a child and teaches kung fu for the Kamon Wing Chun Federation.

Ryan comes from a dancing and fitness background but in the past few years has practised martial arts and boxing.

“We both noticed that, if you wanted to box, you were either only able to do boxercise - and therefore not learning the skills of boxing - or you had to attend a proper fighting boxers’ gym and hire a trainer, which most people find intimidating,” Dearling says.

The couple, both ABA qualified, claim their classes have all you need for a good fitness workout and I reckon they know what they’re talking about.

At 38, both are a year younger than me but in far better shape physically, and their punishing regime leaves me a red-faced wreck, dripping with sweat and gasping for breath.

This is good for me, apparently. I wonder how many calories I’ve burned?

You see, there is method to my madness. I’ve set myself a target of losing two stone in the next three months. I’m giving up takeaways, crisps and beer - although, I must stress, not alcohol altogether.

To help inspire me, I’m putting myself out there by writing a weekly blog on yourlocalguardian.co.uk – complete with my (hopefully) ongoing weight loss, so as to embarrass myself into not quitting.

Having discussed my goals with Ryan, I’m convinced that two BoxLondon sessions a week – coupled with my dietary sacrifices - should see me hit my target.

And so, back to session one… My technique is not bad for a beginner, Ryan tells me as I throw a few tentative punches. I tell her I’m imagining she’s my brother.

It’s like learning to drive a car all over again, so many things to remember at once – keep your guard up, don’t take your eyes off your opponent, watch your stance, keep your elbows in – oh, and don’t forget to duck.

I learn to jab, slip pinches and counter-attack. Ten minutes of being hit in the stomach leaves me thankful I didn’t have a heavy Friday night, before we finish up with some light sparring where we put everything we have learnt into action.

Afterwards, I feel like I’ve gone 10 rounds with Ricky Hatton, but I am buzzing and already looking forward to the next class. So this is what endorphins feel like!

Box London run sessions at Tooting Leisure Centre on Tuesdays (7.30-8.30pm) and Saturdays (11am-noon) for £6.50, and at Wandle Recreation Centre on Saturdays (2-3.30pm) for £7. For details see boxlondon.co.uk