"THE main thing to think about is finishing.”

Those were the wise words spoken to me by my manager at work – a man who has run three London Marathons – before I took on the big challenge last Sunday.

As someone who likes to think he can tackle pretty much anything, and come up smelling of roses (yes, I can be wildly, okay blindly, optimistic at times), I kept in mind a target of somewhere between four hours and four-and-a-half hours to finish the 26.2-mile course, followed by a quick nip home and a few beers to celebrate the day's achievements.

However, events didn't quite unfold as they had done in my naive head over the weeks and months beforehand when I had been piling on the miles during training.

I consider myself a reasonably fit person, and I certainly put in the hours training-wise, but I tell you what, I had no idea how gruelling taking part in the Virgin Money London Marathon would be. I also couldn’t have imagined how brilliant it would be.

Early last Sunday, I jumped off the train at Greenwich Park (joined by a friend I've played football with for many years) for the start of the event. Runners were everywhere, all of them streaming into the park to take on the task at hand for stacks of good causes.

The organisation was superb, so once bags had been dropped off and so on, my friend and I were free to shuffle off to our allocated zones, and await the 10am start with nervous excitement.

Looking at just how many people were taking part caused the enormity of the occasion to settle in.

Once we all got going, it was fantastic to see people lining the streets for pretty much the entirety of the first six miles.

Brass bands were playing, people with microphones bellowed encouragement, and spectators offered Jaffa Cakes, jelly beans and Vaseline for anyone in need. There were even people firing confetti over the runners.

Heading past the Cutty Sark, the crowds became deeper and louder, with the scenery providing a fabulous backdrop (and a good distraction).

The same went for Tower Bridge, which marked a rough half-way point, and Canary Wharf, at about 18 miles.

However, I’ll now forever associate that last place with cramp and muscle fatigue, as these, along with the hot weather, started to play a part.

I managed to stop for a massage at about 19 miles as my calf muscles were really causing me problems, and this helped for a while, but it was at the 20-mile mark that I ventured into the unknown (training takes you up to that but no further).

At that stage a ‘target time’ went out of the window, and I had to start thinking about how to get through each half-mile at most.

I’d be lying if I said stopping didn't cross my mind at that point, as I encountered what must have been the often-referred-to ‘wall’.

What sustained me, and I think many others, was the unbelievable support from the spectators who lined the streets of the capital for the day.

I had my name printed on my vest, so whenever I started to slow I would hear people shouting and encouraging me, telling me to keep going no matter what.

I even got a football stadium chant at one point – “Stampy, Stampy, Stampy”. It didn’t matter whether you had earphones in or not, these people were louder than iPods with volume set to maximum.

The supporters really do carry you home towards the end, so much so that as I headed through Westminster towards the finish line with about one-and-a-half miles to go, I looked up to see charity colours and logos everywhere, people cheering, the wonderful sights of the capital and, thus, managed to power through the final leg as the pain became irrelevant.

Crossing the finish line, I felt I had given everything to get home in a time of 4 hours and 54 minutes.

I really do now understand what people mean when they say that just managing to drag yourself over the finish line somehow – anyhow – is the true accomplishment.

Having run the race, I have huge respect for those who have completed the course in years gone by as well as last week.

And I feel proud to have raised £1,800 for VICTA, the charity that offered me a place in the event. VICTA (Visually Impaired Children Taking Action) was founded in 1987 by a group of parents of children with serious eye problems, and helps affected young people and their families.

Having suffered a sight-threatening condition when I was eight, I was glad to be able to raise money for this little-known good cause.

I crossed the line thinking I would never do it again. But, you know what – two days post- marathon, I was already thinking about when I will be back there.

Paul’s fundraising page can be found at uk.virginmoneygiving.com/PaulStamp.