Organisers of the World Snail Racing Championships are on the look-out for cheats using genetically-modified molluscs.

The event has been running at Congham, near King's Lynn, for around 50 years.

Neil Riseborough, the event's ringmaster, said the championships have never encountered a genetically modified snail, however he said rumours of possible GM entrances began before the days of social media, so it took a no tolerance stance to the matter. Mr Riseborough added rumours focused on mixing snail genes with camel and fish genes to improve stamina and performance in dry conditions and so that snails would be significantly quicker in wet conditions.

Mr Riseborough says the sport has also become highly respected for being dope-free, having stamped out issues through taking slime samples and assessing snails on the day.

Regulation does not always mean the event is controversy free, with one recent issue seeing a Worcester team withdraw as they were unhappy tap water instead of mineral water was used to moisturise the course.

The winner takes home a pewter goblet containing a specially-bred "once in a lifetime" lettuce.

According to Mr Riseborough trainers will have been working in specialised gyms for months, with slopes and climbing frames in place to build stamina.

Mr Riseborough said: "A lot of the serious runners and riders will have been training for months, while amateurs will just pick a snail from the garden on the day."

Jo Waterfield's Hosta won last year's event in three minutes and ten seconds across the 13 inch track, the winning time was one minute and ten seconds short of the two minute record set by Archie in 1995.

The event sees children and adults compete together with 17 nationalities competing last year.

Organiser, Hilary Scase has been running the championships since the mid-80s and says the event began after local villager Tom Elwes first experienced snail racing on a trip to France.

The World Snail Racing Championships will be held as part of the fete at Congham cricket field on Saturday July 20, with snail racing set to begin at 2pm, and the final expected at around 4pm. Both admission and competition entry are free.