One was the world's biggest half-marathon. The other was the world's hariest 7K. On September 21 - the same morning that the Great North Run filled the highways of North-East England with 50,000 runners - the Great Gorilla Run romped 500 fully gorilla-suited souls around the straight-laced streets of London's financial district.

Every entrant was asked to raise £800 for charity, and was given a free suit, complete with hands and feet. It was the only race you could go to where you could wear the full hairy works and be accused of not dressing up. Gorillas in tutus, combat gorillas, Conan The Gorilla - they were all there making funny noises at the start line.

And how was it for a first-time ape? Great fun, but dripping hot, especially at eight-minute miling. Most runners were wise enough to become semi-walkers for the morning. And unless they pinned their head in place, the bouncing meant they soon couldn't see. One way to keep the head in place? Bite the mouth section and breathe through your teeth. For the whole 7K. Now you now why gorillas don't race much...

Forum stalwart Zilla The Gorilla reports...

One of the things that caught my eye immediately was that you got to keep your own gorilla suit - I couldn't resist, the credit card was out of the wallet and before I could stop myself I'd registered online.

I started a forum thread. I was really only expecting a team of four Gorillas as it was the same day as the Great North Run. However, seven weeks later on race day the Runner's World forum team 'Gorillas on the Pist' had 28 members from all over the country, including an ultra runner, several beginners, a Runner's World editor (thanks Sean) and a Korean film crew.

I don't think anybody expected the race to be a 'normal' event. When the costumes arrived about three weeks before race day, people began wearing their gorilla suits to work; we also organised a few 'dry runs' including six gorillas running and dancing our way around Covent Garden and three gorillas climbing trees at lunchtime in Regents Park.

Race-day saw hundreds of gorillas gather on the steps of the London Underwriting centre near the start. The range of costumes was incredible - ranging from just the gorilla suit itself to an elaborate 'man in cage'. Our own team included a viking, an army gorilla, a pink tutu, tartan, horns, rabbit ears and many more.

The silence so familiar at the start of races was in this case broken by a single soft "hoo-hoo". This was followed by someone else replying with an "eeek-eeek" and suddenly the whole place erupted with hysterical ape noises and we were off.

The weather was surprisingly warm and the suit was quite baking. I settled to a nice pace that allowed me to wear the head and not hyperventilate too much on the way round. For a first-time event the organisation and marshalling was excellent, and tourists stood in amazement or took photos as gorillas ran, walked or unicycled past them. The view from over Tower Bridge for me was a speedy gorilla (forumite Natnif) about to be discouraged from throwing bananas at David Blaine by his security people. Spectator support was well spread out throughout the course, which also sported two well placed water stations.

The first finishers returned sometime around 26/27 minutes. Apparently the race organisers forgot to start the clock - they realised a couple of minutes into the race and started it from three minutes. Nobody really minded - in fact it fitted in with the rest of the event as being more than a little surreal.

All finishers were welcomed by a good crowd of spectators cheering them in and were met with water, bananas and a goody bag. The prizegiving was in the local Bar Med and a few of us stayed on to see the forum team win the 'Largest Team' prize. The charity has raised in excess of £100,000 from the event so far, and I have to say I've never cared less what time I finished in.

So the Great Gorilla Run was a huge success for organisers and immense fun for participants. It has left some of us openly suffering from 'gorilla suit withdrawal' symptoms. Fortunately, the people at Dian Fossey are looking into organising a Gorilla film screening and Gorilla Christmas party - and more importantly the event is being run again next year on Sunday, September 19. I can recommend it - and we'll be back - doubly practised!