Leeds United have apologised to Derby County and issued a statement saying they will remind head coach Marcelo Bielsa of the club’s principles of "integrity and honesty" in the wake of the recent spying revelations.
Police were called to Derby's training ground ahead of Friday night's game with Leeds in the Sky Bet Championship amid claims a member of United's coaching staff was surreptitiously watching the session.
Bielsa subsequently admitted before Leeds beat the Rams 2-0 at Elland Road that he had sent someone to spy on Derby, and the club have now issued a response in which they confirmed they have met with Derby officials.
"Following comments made by Marcelo Bielsa yesterday (Friday) the club will look to work with our head coach and his staff to remind them of the integrity and honesty which are the foundations that Leeds United is built on," read an official statement from Leeds United.
"Our owner Andrea Radrizzani has met with Derby County's owner Mel Morris to formally apologise for Marcelo's actions.
"We will make no further comment on this matter."
The Football Association is investigating, but, following Friday night's win, which saw his side move five points clear at the top of the table, Bielsa refused to rule out continuing to employ the same 'spy' tactics.
"I'm not trying to justify anything," he said. "I've just explained why I feel I'm not a person who cheats and why I accept any reaction this behaviour creates.
"Things are as English football says. I have to respect the habits and traditions of this country.
"I would accept any sanction the club takes against me and any sanction the federation takes against me, and also the judgement of Derby County.
"This episode affects me. Of course the win is important. The only thing I'm going to apologise for is to have contaminated a football game with this subject.
"If I was a child, I would say I won't do it again, but I wouldn't feel right responding like this and would lose credibility.
"I won't say that I won't do it again. It's a childish position to answer like that."
Lampard had no complaints about the result but suggested the FA needed to take firm action.
"It's not for me to say what happens," the former Chelsea and England midfielder said. "I believe there's not an absolute clear-cut rule about it.
"But we can't open the door to this thing happening every week. What kind of farce would that be? Everyone sending undercover people, drones etc into training. It would be farcical.
"Something has to be done. I don't know what it is, it's not my decision."
Lampard felt Bielsa had acted against the spirit of the game and insisted he would rather quit coaching than employ the same tactics.
"Cheating is a big word," he added. "If you talk about details and gaining advantages, great and good managers do that.
"But this one is over the line. It's not just a toe over the line, it's a hop, skip and a jump over the line.
"I'd rather not coach than send people undercover on their hands and knees with pliers and bolt cutters to go and look at the opposition because I respect the opposition."