Forensic testing will be used to crack down on cheats in a village conker competition.
Contestants at the Poulton International Conkers Tournament have been warned that they face searches and police-style checks if judges suspect foul play.
The contest is being held in the village near Cirencester, Gloucestershire, on October 2 after a break of 10 years.
Conkers collected and checked by the contest committee will be handed to competitors to use in the tournament.
They will be marked with a special fluorescent pen, similar to that used by police forces to highlight stolen property.
The winning team will then have their conkers checked by a special light to verify that they are not substitutes.
Organiser Phil Heneghan said officials are on the lookout for 'illegal' conkers and may also bring in footwear checks.
"It is truly incredible what lengths some contestants will go to in their attempts to win the championship," he said.
"All conkers used will be supplied to competitors by the committee, after being individually drilled and strung, in an effort to avoid the dishonest substitutions experienced in the past.
"We got the idea for the fluorescent marking from the police scheme to ensure that the conkers are genuine and have not been substituted with conkers that have been soaked in vinegar or put in the oven."