When I agreed to take part in a boot-camp training session, visions of myself dressed as Private Benjamin, getting screamed at by an angry sergeant raced through my mind.

Pushing these scary thoughts aside, I plucked up the courage to give Four Seasons Fitness’ group a try – I’m desperate to lose some weight for my upcoming nuptials, after all.

I never imagined running around a football pitch in the freezing cold after a hard day’s work would be the best way to spend Tuesday evening, but then what do I know?

From the minute I arrived at Bexley Park Sports Club, essential bottle of water in hand, my nerves subsided after meeting friendly instructor Ben Campbell – a far cry from the terrifying soldier I’d pictured.

Regular and new members, all women, began turning up as Ben jotted down my measurements – something he does each month to monitor everyone’s progress – and I vowed to drop the cake and tighten my 29-inch waist over the next few weeks.

Around 10 ladies turned up for the workout, and if you’re intimidated by joining new groups there is no need to be here.

Everyone’s in the same boat and although they work extremely hard to achieve their goals, an overriding sense of fun unites this group and new faces are warmly welcomed – especially by Oakley the chocolate Labrador.

This 11-year-old is the only bitch in the club and even she has lost weight since joining with owner Amanda Larkin, 43, in October last year.

We warmed up by running three laps of the pitch, after which we were put in pairs and told to punch each other.

Don’t worry – there are boxing gloves and pads involved too.

A succession of intense exercises followed including painful press-ups and sitting down and passing a heavy ball between each other whilst constantly keeping our bent legs in the air (amazing for abs).

Incredibly affective exercises to strengthen our arms, stomachs, legs and bums followed until every single muscle – including ones I never realised existed – had been worked on to the beat of today’s chart toppers.

I was teamed with the fabulous Ellie Nunn who, despite not being a trainer, talked me through exactly how to do each gruelling workout as we giggled and gasped through it all.

The 26-year-old is a true testament to the boot-camp, having lost a massive two stone since she started the sessions in June last year.

Ben, she told me, has helped nutrition-wise too and helped her curb a serious Haribo addiction.

We changed partners three times over the course of the hour-long boot-camp and I realised this isn’t just a training session – these girls are real friends.

Ellie has even given Oakley a flashing collar to reward her motivational barking.

Lying on a cold mat with my hair getting muddy to match my chin from when I collapsed mid-press up, I cycled in the air and looked up at the stars in the night sky.

Rather than bully, Ben circulates the group to make sure everyone’s got the right idea and shouts words of encouragement throughout the session.

The hour flew by and, although my body had definitely reached its limit (I think the lunges and squats were to blame), I can honestly say I’d never felt more energised on a work night.

I know this session works because since then I have not been able to walk properly, lift a cup to my lips or get dressed without crying out in pain - but it was definitely all worth it and I highly recommend it.

Boot camp sessions at the Calvert Drive centre cost from £38 a month and run from 9.30am on Monday, Wednesday and Friday, from 7pm on Tuesday and Thursday and from 9am on Saturday.

For more information visit fourseasonsbootcamp.co.uk