Leeds coach Marcelo Bielsa upped the ante in the 'spygate' row on Wednesday when he admitted he had snooped on every team his side had faced this season.
Police were called to Derby's training ground last Thursday to escort away a man "acting suspiciously" on the perimeter of the complex, later confirmed to be an employee of Leeds.
Bielsa later admitted that he was responsible for the decision to spy on Derby, and said at an impromptu briefing on Wednesday that it was part of his preparation for every Championship match so far.
Here, Press Association Sport looks at occasions where teams and individuals tried to gain an extra edge.
The original Spygate (Formula One)
McLaren were fined 100 million US dollars and thrown out of the constructors' championship in 2007 for being in illegal possession of Ferrari's entire technical data. The 780-page dossier was leaked to McLaren by disgruntled Ferrari engineer Nigel Stepney. Fernando Alonso, who was caught up in the email exchange of the illicit information, threatened to tell all to the sport's world governing body the FIA unless he was granted number one status over Lewis Hamilton – a demand that brought about his acrimonious departure from the British team after just one season. Stepney meanwhile, was sentenced in Italy to 20 months in prison. He died in a road accident in 2014, aged 56.
British and Irish Lions tour (rugby union)
Lions head coach Warren Gatland claimed his side's training sessions prior to their warm-up match against Queensland Reds and ahead of the three-Test tour against Australia in 2013 had been recorded on video. Gatland said members of his coaching staff chased away a mystery man, attempting to film his squad. Australia denied any wrongdoing and accused the Lions of creating a sideshow. Gatland later back-tracked on his initial claims.
Genoa coach "hid like Rambo" to spy on rivals (football)
Back in 2013, Italian side Genoa suspended one of their coaches after he was found spying on a training session held by city rivals Sampdoria. Luca De Pra, a youth-team coach, was said to be hiding in bushes while dressed in camouflage gear. In a statement, Sampdoria said De Pra was hiding like "Rambo under a tree". Genoa, who denied any knowledge of De Pra's activities, won the ensuing match 3-0.
Man detained ahead of England World Cup semi-final (football)
All 23 members of the #ThreeLions squad trained in Zelenogorsk today. 👍 pic.twitter.com/VjE6hNiUUZ
— England (@England) July 9, 2018
A man was arrested ahead of England's World Cup semi-final against Croatia last summer, suspected of spying on Gareth Southgate's side. The man was accused of acting suspiciously on a roof, 180 metres away from England's training base. He was asked to delete panorama photos and then released without charge.
