SOME people are natural runners. I am not. But when the women's editor asked me to do the Race for Life, my challenge was to make it the whole way round the course without walking once.

There were three weeks to go when a training planner, sponsorship form and race number arrived through the post.

Day one of the planner said rest, which was encouraging. Days two and three I had to work late, and by the time I was home I convinced myself it was too dark to go out for a jog.

There were no more excuses by day four, so out came my ancient, smelly trainers and a pair of shorts. I decided to take my dog out for a bit of moral support. She thought it was great fun getting under my feet, pulling me sideways or stopping suddenly to sniff a rabbit hole.

We struggled along for ten minutes and I'd had enough. My arm was almost pulled out of its socket so that was the first, and last, time I went out running with a red setter.

With only two weeks to go I changed tactics and out came the sponsorship form. I decided that with so many people's money gathered up, it should spur me along to put in a good show on the day.

People were amazingly generous when they heard what Race for Life was all about. More than a few promised extra money if I really managed to run all 5km.

As the race day loomed I needed a kick start in the self motivation department. With no one to check up on me, I kept slowing to a natural stop, enjoying a pleasant stroll in the countryside instead of the dedicated training programme I was supposed to be following.

My boyfriend appointed himself as personal trainer and started coming with me to provide some moral support. But as he was on a bike I felt a bit cheated somehow, and passers-by gave me sympathetic looks as I puffed along.

Suddenly there were just days to go. I started having nightmares about the race, which my colleagues found hilarious. I dreamt the features department were making me run with a full army rucksack, wearing enormous army boots, and that I got lost and couldn't find the end of the race. In another nightmare the grass was so long my legs were all tangled and I was rooted to the spot. I even dreamt it was like an assault course and we had to clamber over the horse jumps.

By yesterday morning it was a relief to get to the venue. Music was blaring out as 4,000 women started a gigantic aerobics warm-up session together. The atmosphere was amazing and everywhere you looked there were families and groups of friends ready to take part.

Everyone had been provided with signs to wear on their backs, saying who they raced in memory of, or who they ran in celebration of. It was humbling to read. A lot of signs simply read mum, and as I waited with my own mum before the start of the race I felt so privileged to be one of the lucky ones. I have watched as friends lose their mums to cancer. But I would never pretend to imagine I could know how hard it is.

As we counted down to the start of the race there was an enormous feeling of togetherness. I felt proud to be there doing my bit, and although it might sound corny it really felt as though we were all there to make a difference.

I managed the whole thing without stopping to walk, and I even finished in less than 30 minutes - not record-breaking, but an achievement for me. But by far the most important point was that I had been a part of something which felt so worthwhile.

On my sign I wrote: I Race for Life in celebration of researchers everywhere.' My boyfriend is a molecular biologist for a cancer research charity, and he works in a lab on complicated experiments involving spo-11 induced DSBs'. I can't pretend to understand anything he does. But I know that a cure for cancer isn't possible without organisations such as Cancer Research UK. And their work wouldn't happen without the enormous fund raising which we were a part of yesterday.

For me next year's challenge won't be to run 5km as fast as I can. I want to make sure as many of my friends and family as possible make Race for Life an annual date in their diary. The motto for Cancer Research UK couldn't be more apt - together we will cure cancer faster.