British Military Fitness

USP: Get fit in the outdoor with loads of others.
These guys have classes all round London and the rest of the UK. I have been to the ones in Hyde Park and Battersea Park.
You work out for a good hour and you feel great afterwards — if a bit muddy. The stiffness kicks in a couple of days later, but I burned through that with another class and within a week or two I was taking it all in my stride.
Great social way to get and keep fit, especially if you find it hard to motivate yourself to work out properly when you are in the gym. Thoroughly recommend it — maybe see you in the park.
… oops, writing this and I have missed a class. Have to make it up tomorrow morning …
Enjoy!
Edit: Since writing this review, I have taken a job with British Military Fitness.