Manchester Police have launched an investigation into threats against Malcolm Glazer and the Manchester United board by a supporters group opposed to Glazer’s attempts to buy the club.

In a statement posted on the Red Issue website, the group, calling themselves the ‘Manchester Education Committee’, claim to have been monitoring the movements of the Glazer family and state they will “ensure a warm welcome” for any family member visiting England, “no matter how large the phalanx of bodyguards”.

The group said they would regard the United board as collaborators if they recommend Glazer’s bid to shareholders.

“Police are aware of comments made on the ‘Red Issue’ website,” a police statement said.

“Appropriate measures will be put in place to deal with the comments and an investigation is under way.”

The group have in the past admitting vandalising the house and car of former United club solicitor Maurice Watkins, after he sold shares to Glazer.

They also invaded the pitch during a United reserve match last year.

Glazer submitted a fresh £800m bid to take over United on Monday.

He has built up a a 28.1 percent stake in United but has been turned down three times already.

The threats were made as it became clear that the United board is virtually certain to allow Glazer to conduct due diligence, the process of checking a company’s financial books.

United supporters are concerned that to fund his takeover, Glazer would be forced to borrow cash which would ultimately be recouped through subsequent profits made by the club.