Former Manchester United midfielder Nicky Butt has described the botched Super League launch as the “worst case of bullying”.

United were among six Premier League teams who signed up to the breakaway competition, before being forced to withdraw in embarrassing fashion on Tuesday.

Executive vice-chairman Ed Woodward has already announced he will resign at the end of the year, while co-chairman Joel Glazer is also under pressure to depart.

Glazer wrote an open letter to United fans on Wednesday to apologise for the club’s involvement in the project.

But Butt, who left his role as the club’s head of first-team development this week, does not believe the letter counts for much.

“I don’t think an apology is too great anyway if I’m honest,” he told Sky Sports. “I think what happened should never have happened.

“What happened is the worst case of bullying in my opinion, from powerful people, so whether they apologise or not is irrelevant to me really.”

In the letter, Glazer pledged to “rebuild trust” with the club’s supporters, but Butt does not see a way back for the American.

“[It will take] A hell of a long time and I don’t see how it’s possible,” he added. “It’s difficult to regain someone’s trust after going behind people’s backs for so long. It’s going to be difficult, I don’t know how they do it.

“I think that’s how some of these businessmen work. They work in the shadows if you like and they do what they think is right, but I think the shocking thing is they can’t have empathy for the fans who make this sport so great.

“Without the fans, the sport is nothing, and to not be on board with what the fans want, that’s the alarming thing for me.

“So it’s a lesson to people who come into the country and come into powerful football clubs and think they can do whatever they want because they are owners and they are very, very wealthy.

“Over the past few hours in this country it has proved not to be the case.”

Butt has clarified that his departure from Old Trafford is unrelated to the Super League plans.