A hanggliding enthusiast claims he is owed £30,000 prize money by the Worthing Birdman competition, a court heard.

Stephen Elkins competed in the popular seaside event in 2009, with the jackpot on offer to any competitor who flew 100m from the pier.

He claims he flew about 102m and is owed the prize money, but organisers Worthing Town Centre Initiative said they had measured his flight at 99.87m, an agonizing 13cm short of the prize line.

At Brighton County Court yesterday representatives for Mr Elkins said the measuring tools used by the event were “not fit for the purpose determining distance in this competition”.

Hugo Page QC, speaking on behalf of the claimant, said the device, called a Winklefix, had an error margin of plus or minus 3m.

He added: “The readings taken by it, which are also wholly uncheckable, are useless for determining where the flight ended within that range.”

The claimant argued the true distance travelled could be determined using five factors - the length of the tether of a buoy marking the 100m point (argued to be 8m), the buoy being anchored at least 100m from take-off and probably further, the position of a video camera that captured the flight, the distance south of the buoy line (argued to be 11m or less) and Mr Elkin's head apparently 1m past the buoy.

Previously in the case two experts had agreed these points would lead to a distance flown of about 102.7m, meaning Mr Elkin should have been awarded the £30,000.

Clifford Darton, representing the defendant, said the use of the Winklefixes, a builders' tool used to plot a point, was in the competition's terms and conditions and using five other points “all got rather vague”.

He said: “Winklefixes remained the best option. Contractually that was agreed.”

He likened the scenario to a fan with mobile phone footage trying to overrule the decision of a try after a rugby match had ended.

Mr Darton added: “Whether this comes down to the best view [of Mr Elkin ending his flight] was from the pier or the 100m mark or the lido where the camera was on, what is absolutely certain is the best view is not hindsight, and that is what you are being asked to try this case on.”

The case continues.