I have never entertained the idea that I might be good at the army. I wouldn't mind some military-style fitness, but I don't like the idea of someone shouting close to my face and calling me useless. I get enough of that at home.
There is a way, however, to get army-fit without someone shaving your head first. British Military Fitness trains commoners in parks around the country, providing a cheap and unponcy alternative to the gym. I arrive in Hyde Park at sunset to find camouflaged instructors - all serving or former members of the armed forces - passing out numbered, coloured bibs: blue for beginners, red for intermediates, green for the super-fit. I pick red without hesitation. I am one of nature's intermediates. Unfortunately there aren't enough intermediates to form a group, so we're thrown in with the greens. Suddenly we're off at a run, doing laps while being barked at. "Number 8!" shouts the instructor, meaning me. "Why aren't you in a green bib?" I don't think I'm supposed to answer, but I can't anyway. I'm panting madly, about four minutes in.
A quick rest does not appear to be an option. There are press-ups to be done, and more running. Even when we are listening to instructions we are expected to run in place. It's too dark to tell if I am the only one on the verge of tears.
I have to carry a man on my back while running. Then more press ups. At first I was reluctant to put my hands in the mud, but now I wish to lie face down in it. There comes running in single file, the backmost person being required to overtake everyone else in turn, followed by abdominal exercises of unspeakable cruelty. I am making little squeaking noises, but I carry on, my will broken.
We finish with a sprint back to the car park. Later on I will experience symptoms of tiredness I have never known - too tired to work a knife and fork, too tired to roll over in bed - but for now I am happy to go home. Then I remember I've come on my bike.
Next week: Lucy Mangan welcomes the spring.