The UK may not have the climate for luxuriant fly-and-flop spa holidays, nor the natural resources for therapeutic thalassotherapy breaks, but it does have bracing elements, rugged coastline and dense woodland — a combination that suggests not so much a delicate Cathy in search of her Heathcliff as a modern-day Private Benjamin seeking hardcore fitness of the triumph-over-adversity kind.

Cue the rise and rise of boot camps, fitness holidays that offer serious military-style training in the countryside, and are the latest exercise craze to sweep the nation after the success of British Military Fitness in London’s parks. Forget your stern but polite personal trainer and a plush gym — this is about mud, sweat and even tears in your bid for lean thighs and fine-looking abs.

My own week-long experience took place at No 1 Boot Camp, in Somerset, with a crash course for fitness and weight loss. Within half an hour of our arrival, two straight-faced instructors in full naval rig, Ronnie James Hughes and Dean McConville (pictured right — Staff Hughes and Staff McConville to us), laid down the rules. After a strict telling-off for giggling across the table, I realised that the military theme was not confined to the fitness sessions. It’s best behaviour at all times or you risk a punishment card condemning you to 50 press-ups or a pool soaking.

Each member of the group (which consisted of everyone from hoteliers to housewives) was weighed, then we were given three laps of the lake and a minute of as many sit-ups as we could muster to test our fitness. We were all left raspberry-faced and gasping. There followed a surprisingly pleasant two-hour hike — a slow ramble through the neighbouring woodland and up to a clearing with views across Exmoor, with just the odd laborious interlude when we were given a hefty log to carry together.

This mixture of intensities is a large part of what sets No 1 apart from some more hair-shirt-style boot camps; it sits nicely on the pleasure/pain threshold.

So, while we were up at 5.30am to conduct a mock-military operation, the surrounds, historic Knowle Manor House, near Dunster, feel more like a cosy country guesthouse than a barracks. And, though your stay will be bereft of alcohol and sugar, and sparing in carbs and caffeine (just one cup of filter coffee with soya milk is permitted at breakfast, as the withdrawal symptoms are considered too unpleasant when coupled with the exercise and restricted diet), the presence of the former Oxo Tower chef Pete Cookson means that the food is delicious. We refuelled on Cajun chicken salad, minted pea soup and salmon on a bed of pak choi. In the evening you can treat aching muscles to a decrunching session with Elle Macpherson’s massage therapist, Leanne Wright, an expert at exterminating troublesome spots.

Still, by day three, known at camp as Toxic Tuesday, the vigorous regime — boxing circuits, bleep tests, increasingly intense hikes — started to take its toll. I developed a slight knee injury, while several girls were reduced to tears by a formidable punishment session that had the group crawling from one end of the exercise barn to the other, all the while being bombarded with obscenities so vile, decoding them was like doing a brainteaser. The upshot, however, was a sense of solidarity and a fresh will not to give up — which, it turned out, was our trainers’ aim all along. “We want to create a siege mentality so that the guests bond and turn to each other to beat us,” Hughes explained afterwards.

It worked. We started pulling together as a team, making sure we all assembled on time for activities and urging each other on. And, although I had to endure nine minutes in an ice bath to assuage my gammy knee, with Staff Hughes guarding the door, the level of care was remarkable. The trainers were always mindful of everyone’s corporeal niggles and adapted sessions to suit.

Together, we flipped tyres up hills and through streams, pushed 4WDs down country lanes at 6am, rescued “casualties” in the form of weighted bags. “We do a lot of team work, moving things from A to B — not just pure physical stuff,” Hughes says. “Flipping two tyres up and down a hill probably burns about 750 calories, but the mental aspect distracts you from the physical exertion.”

I was surprised not just by how quickly my muscles snapped into shape, but by how the regime improved my whole person; I developed a newfound grit and determination, and saw similar changes in my fellow boot-campers. Once-shy girls became respected leaders during our mock-military operations, while others who had threatened to leave at the start manifested a steely will to see it through.

Most, however, had come for weight loss, and they saw results: several lost 6lb; a couple lost an impressive 10lb. We also all learnt valuable lessons in teamwork and willpower — which will last far longer than a suntan would have done.

A week-long stay in a shared room at No 1 Boot Camp starts at £995; no1bootcamp.co.uk. British Military Fitness starts at £35 per month; britmilfit.com

Where else to stick in the boot

New You Boot Camp, Wales; newyoubootcamp.com Military physical instructors whip you into shape through a challenging assortment of treks, cycling, abseiling, boxing and obstacle courses. The Signature camp (from £1,225) includes private rooms and more palatable food; the Back to Basics (£950) is totally frill-free, with army-style bunk beds, communal showers and cheaper food for those who want to ramp up their suffering.

The Camp, Scotland; thecamp.co.uk You’re on the move, performing low-intensity exercise, such as mountain-biking and orienteering, from 5.45am until 10pm at this women-only camp in Galloway, southwest Scotland. The level of expertise, which includes on-site medical experts, a physiotherapist and nutritionist, is reflected in the price. A week’s stay costs £1,750 for a private ensuite room.

Total Boot Camp, Peak District; totalbootcamp.co.uk Bunk beds and daily room checks for contraband give this weight-loss and fitness camp an authentic military flavour. Plus points include consultations with the nutritionist Marisa Peer, an expert in eating-related disorders, and workshops with a style and colour adviser or a confidence coach. Mixed and women-only camps are available; from £725 for five days.

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