Middlesbrough has lodged a formal complaint against Southampton, alleging unauthorized filming at their training ground, Rockliffe Park. This incident occurred just days before the two clubs are set to face off in the first leg of their Championship play-off semi-final at the Riverside Stadium. The complaint highlights the seriousness of the situation, especially with a potential £200 million prize for the overall play-off winner. A member of Southampton's backroom staff was reportedly caught filming Middlesbrough's training session, prompting the club to take action. Middlesbrough's head coach, Kim Hellberg, was conducting a significant training session when the incident took place. A Middlesbrough employee noticed the individual loitering near the golf course adjacent to the training ground. Upon confrontation, the individual fled the scene, raising further concerns about the integrity of the upcoming match. The English Football League (EFL) is now investigating the matter, treating it as potential misconduct under their regulations. This incident echoes past controversies in football, such as the case involving Leeds United in 2019, where similar allegations led to a hefty fine. Middlesbrough and Southampton have both been approached for comments regarding the situation.