London (AFP) – Championship leaders Leeds will be under a formal Football League investigation following Marcelo Bielsa’s admission that he instructed a member of staff to spy on a Derby training session.

Leeds manager Bielsa revealed he was responsible for sending the man to watch Frank Lampard’s Derby in training on Thursday.

Bielsa claimed the practice of spying on opponents was common in his native Argentina.

Derbyshire Police were forced to intervene and move the individual on, while Leeds have since apologised to Derby and said they will remind Bielsa of his responsibilities.

Bielsa’s side beat promotion rivals Derby 2-0 24 hours later to cement their four-point lead at top of the second tier as they chase promotion to the Premier League.

But the Football Association has begun its own probe and the Football League has followed suit.

“The EFL has today written to Leeds United requesting their observations in regard to an incident that took place in the vicinity of Derby County’s training ground on Thursday 10 January, 2019,” an EFL statement said on Tuesday.

“It follows a complaint from Derby County who allege that an individual, acting under the instruction of Leeds United, sought to observe a private training session the day before the two clubs were due to meet in the Sky Bet Championship.

“The EFL has now determined that it is appropriate to consider this matter in the context of a number of EFL regulations whilst also noting that the alleged actions appear to contravene the Club’s Charter that all EFL clubs agreed to in summer 2018.

“The decision to progress this matter to a formal investigation comes as a result of the club’s manager, Marcelo Bielsa, admitting to instructing an individual to undertake the acts being complained of in a television interview broadcast on Sky Sports on Friday, January 11, 2019.

“The Football Association has also confirmed they are considering the same matter in line with its own rules and the EFL will work with its FA counterparts to ensure that any potential action taken does not prejudice those investigations being undertaken. “