It's a long way to Twickenham, a very, very long way

Last week, there was a slight mistake in my column. This charity walk will last for four weeks – not 10. I only mention this because I can already tell you that, once my month is up, I won't be able to do an extra six minutes, let alone six weeks.

I am totally knackered now and, if I did have to go on beyond the original schedule, I would be left with no alternative but to cheat. If push comes to shove, I have a brother who looks quite like me and could take over relatively unnoticed.

It has been one hell of a week and my poor body really doesn't know what's hit it. I don't know exactly how painful childbirth is, obviously, but I can assure you this is the closest I have come to it. I have never been in so much pain. Honestly, I would rather face 10, no make that 15, Jonah Lomus than do this walk. It's that tough, and I just have the utmost respect for Ian Botham, who has completed seven of these treks. That is simply incredible.

I have tendinitis in my ankle and, although it can be very painful at times, I have had it checked out and there is no structural damage. You know what that means? Yep, I can keep walking. Great.

And walk we have. More than 200 miles in the first week and more of the same planned for next week. At least I have seen some familiar faces along the way: Phil Vickery saw me out of Gloucester; James Bramhall and Dan Harris guided me to Sale's ground; and yesterday, the rugby league stars Denis Betts and Andy Johnsone walked the first hour from Salford. Thanks, guys.

The highlight of the week was definitely meeting Emma Dajavs. Emma is just 26 and, two years ago, was diagnosed with leukaemia. She had such a violent chemotherapy treatment that the doctors at the time told her that she would never be able to have children. So you can imagine how proud she was to bring little Maddy, who is almost two, along on Tuesday. Jessie, her nine-month-old daughter, stayed at home but the fact that Emma had managed to produce what she calls "two little miracles" really brought home to me what this charity walk is all about.

I know it sounds obvious, but these human moments are very important for me. They remind me that most of us are pretty fortunate and that there are people who need our help. I received an e-mail from a mother informing me that her daughter had contracted leukaemia since our walk started. Like so many others, money is what she needs. So far we have raised £70,000, so thank you. Don't stop there, though. Despite the aches and bruises, I'm certainly not planning to give up.

If you think I'm suffering, you should have witnessed Steve Rider on Wednesday. This is going to sound sadistic, but I really enjoyed watching him struggle. As you know, Steve never has a hair out of place when he is on the television, so seeing him at the end of the 21 miles was something else. He started calm and collected, but, when there were about five miles to go, I looked back and saw that he was in a pretty bad state. There was mud seeping out of his trainers and I got the distinct impression he would rather have been somewhere else. "Just an hour-and-a- quarter to go," I told him. You should have seen his face.

At the end – and yes, to his credit, Steve did reach the finish line – he was interviewing me for yesterday's Grandstand. You couldn't see it, but the cameraman was actually holding him up and then had to lead Steve to the Tetley's double-decker bus. Poor old Steve looked like a vampire had been at him. He got back to London so beat up that I even received a call from the Grandstand producer thanking me for nearly destroying his presenter. Steve might have looked OK in the hot seat yesterday, but a little dicky bird tells me that his feet were still so sore he had to wear slippers.

Steve's support, like that of all those of you who have turned up and donated to the cause, has been much appreciated. Walking for hour after hour, day after day, is really difficult. And I'm not just talking about the physical aspect. When you're in busy towns, time flies and you don't feel any pain whatsoever. It's when you're ambling along a long, deserted road that you wonder what you're doing. Thank God I've got my best mate, Chalky, to chat to. We are slowly covering every topic under the sun and I am beginning to worry that it won't be long before we've run out of things to say to each other.

One person who's never been short of an opinion or two is my old Bath and England team-mate Victor Ubogu. He has kindly accepted an invitation to join us next week and I look forward to putting him through his paces now that we've got him away from his London bar. Not that there will be any drinking. I'm rather embarrassed to admit this, but I am in bed at 9.30pm every night at the moment.