If you're looking for an event that will test you both physically and mentally the 24 hour Three Peak Challenge of Ben Nevis, Scafell Pike and Snowdon should do it. Did I mention it also burns around 8,000 calories?

A nice walk in the country followed by a long pub lunch takes some beating, but anyone can do that. If you want to test your metal, the three highest peaks in Scotland, England and Wales are a good place to start, but unless you are a very experienced walker/hiker make sure you cough up for a guide and a driver. It's always going to be hard work, but they will ensure it isn't a miserable experience.

Our group of 8 set off for the peak of Ben Nevis at 6am on a drizzly June morning. The Adventure Cafe guide Ian had warned us the day before that it wasn't unusual for at least one or two members of a group to throw in the towel on the first mountain. As my legs began to seize up 30 minutes into the climb I began to worry I'd be that person. The first rest stop wasn't for another half an hour and I was really struggling. However it's amazing what sheer-bloody-mindedness and a handful of Jelly Beans can do. We made the snowy summit surprisingly quickly in 2 hours and 30 minutes.

Back in the mini bus we were faced with a five hour drive from Fort William to Scafell Pike in the Lake District (pictured above). Ian encouraged us to eat as much as possible in this time saying we'd burn as much as 8,000 calories during the 24 hours. We had prepared not to disappoint. The previous evening had seen our group play supermarket sweep; chocolate bars, sweets, nuts, cakes, crisps, sandwiches, pasta pots, flapjacks, cereal bars, pies, sausage rolls, our shopping lists read like a calorie orgy.

Fuelled and ready to go we took the Corridor Route from Seathwaite. Blue skies and sunshine made a nice change from the snow and rain on Ben Nevis and meant we could fully appreciate the views. The summit is 3,209 ft and on really clear days you're supposed to be able to see the Isle of Man. I couldn't, by the time I'd reached the top all I had the energy for was another chocolate bar and a lie down on the floor. However it was impossible to ignore the beauty of the Lake District and I made a mental note to visit again under less time pressured circumstances.

Descending the boulder fields and scree of Scafell Pike knees began to complain loudly, but we managed to reach the minibus before the last light faded around 10pm. We just had time to find the toilets and refill our water bottles before we were bumping our way down windy country roads on route for our final challenge, Snowdon.

Geeky looking they may be, but head torches are an essential piece of kit for climbing a mountain at 2.30am. We spent the first hour climbing silently in the dark - stunned into a stupor by the thought of how we were choosing to spend our Saturday night. It was pretty surreal, all you could see were the head torches of those bobbing in front of you and the occasional flash of light from some very hardy climbers a few ridges ahead. As we neared the top the climb became steeper and began to really take its toll on already tired legs. Our little group had slowed to what felt like more of a shuffle, but sunrise gave everyones' spirits a lift as we were finally able to see where we were and just how far we had already come.

The last stretch to the top past the newly opened cafe (rather unfairly shut at 5am) and the train tracks seemed to last forever. Everyone had some complaint; backs, knees, thighs, even bums and the mountain didn't exactly welcome us. The summit was clouded in thick, cold cloud. Not that it mattered. We didn't have time to hang around with a 24 hour deadline to beat. We just had time to take a few hard earned photographs and cram in another chocolate bar before we were on the way down towards the finish line and a well deserved cup of tea.

Our team finished the challenge in 23 hours injury free, apart from a few minor aches and pains. It was a great challenge, tough, but fair, perfect for motivated group of friends. The sense of achievement on completing the course is very satisfying and if you go that bit further and raise money for charity, it makes everything you go through seem very worthwhile.

How to go about it
There are dedicated outdoor pursuits companies like Adventure Cafe and Mountain and Glen who specialize in this kind of challenge and charge around 400GBP for the pleasure or you can do it through a charity such as MIND or Youth Cancer Trust. Both of these charities take part at least once a year as part of their fundraising initiatives and provide training plans, guides and drivers.

It's a tough challenge, but if you're reasonably fit and take the training seriously, it's one you'll never forget.