Middlesbrough believe they caught a Southampton analyst hiding in the bushes and allegedly recording their training session on Thursday morning, in a remarkable repeat of the 2019 Marcelo Bielsa “spygate” affair.

Boro have reported the incident to the English Football League as spying on opposition training is in breach of their regulations. The EFL is investigating the alleged misconduct and have requested Southampton’s observations regarding the matter.

The individual, thought to be part of Tonda Eckert’s backroom team, was spotted by a member of Middlesbrough staff at the beginning of their session at Rockliffe Park, 48 hours before their Championship playoff semi-final first leg.

Boro are aware of the details of the Southampton employee allegedly involved. It is thought the individual in question logged video and photographs on his phone, potentially focusing on Boro’s set pieces, but refused to identify himself after being confronted.

An EFL spokesperson said: “The EFL has written to Southampton FC requesting their observations following a complaint from Middlesbrough FC relating to alleged unauthorised filming ahead of the two clubs meeting in Saturday’s Championship playoff semi-final first leg.

“The alleged incident is said to have taken place on Middlesbrough’s private property by an individual identified to be associated with Southampton. The league is treating this matter as potential misconduct under EFL regulations and will be making no further comment at this time.”

This incident, first reported by the Daily Mail, is bound to add spice before they meet this weekend. Middlesbrough entertain Southampton on Saturday before hosting Kim Hellberg’s side in the return leg at St Mary’s on Tuesday.

There is a similarity to Bielsa’s time at Leeds when he instructed a colleague to observe Derby’s training before a league match. Bielsa later admitted to spying on all of their opponents that season.

Leeds were fined £200,000 and reprimanded by the EFL after the club admitted a breach of the rules, which state: “In all matters and transactions relating to the league, each club shall behave towards each other club and the league with the utmost good faith.”

Middlesbrough did not comment. Southampton have been approached for comment.