HERE'S the challenge. Dress up in a banana costume and, with a five minute head start, run 10km at exactly four minutes 40 seconds per kilometre while being chased by hundreds of other runners.

This was the Bananaman Chase 10k which took place at Willen Lake in Milton Keynes. This was a race organised by Leukaemia Research and which was quite a heartbreaker.

Before the start I met a four-year-old lad who had recently been diagnosed with leukaemia. We chatted and he promised to try to catch me on the run.

On the two-lap course around the picturesque parkland venue, many runners wore t-shirts carrying photographs of loved ones who had died of cancer. Others had simple messages written on their clothes: "In memory of..."

I was privileged to be there, one of 10 bananas who had been asked to set the pace for runners to see how many of these costumed characters they could catch.

The fastest banana was Tony Audenshaw who plays Bob Hope in ITV's Emmerdale. He's run sub-three hours for a marathon and clocked 1 hour 25 minutes at last weekend's Great North Run.

He was asked to set off to run 10km in 45 minutes, I was second and had to pace it at 47 minutes, and so on, with the final banana taking 1hr 45min to complete the distance.

The atmosphere was buzzing. Far removed from the Great North Run, but the spirit was excellent among the 400 runners who took part and their supporters. Cheerleaders lent their support, marshals and spectators were enthusiastic supporters.

It wasn't easy running in a banana costume. Though the course wasn't too tough, bar a nasty little hill after a kilometre, it was warm and running was hard.

Trying to measure an even pace was also difficult, and I was doing mental maths at each kilometre marker to ensure I was keeping pace.

Incredibly, the first runner passed me after three kilometres - and I'd given the youngster a five minute lead to catch up. He eventually clocked 35 minutes for 10km.

I tried to milk the occasion, high-fiving with young spectators, stealing a handful of chips off some teenagers sat on a bench, and even sitting on a bench with a family to take in some water at half way.

I had fun, and enjoyed being part of this significant occasion. Yes, I hit my target, running 47 minutes 39 seconds as 16 runners passed me on the route.

I had a sprint finish with Tim Smith from Team Bradley at the end, as we belted for the line cheered on by the crowds.

A great day and a great cause. A first for running as a banana, but fortunately no slip ups!