While there have been long-standing rumours that the owner of former Superbowl winners Tampa Bay Buccaneers was keen to expand his sporting portfolio, the latest revelations are being treated seriously within the Red Devils camp – and certainly by the fans.

United supporters have already succeeded in preventing Rupert Murdoch taking control of the club when their opposition helped block the BSkyB bid in 1999 and were quick to air their views when it appeared Cubic Expression duo John Magnier and JP McManus – who remain United’s majority shareholders – were considering a takeover.

They remain confident direct action now will break Glazer’s spirit too and are vowing to use any means necessary to block the American.

“We sent Murdoch packing and gave Magnier and McManus a bloody nose,” said Jules Spencer, chairman of the Independent Manchester United Supporters Association.

“If Glazer wants a fight, we will give him one. We want to make it clear that he is not welcome or wanted as owner of Manchester United.”

Representative of another influential fans' group Shareholders United held a Not4Sale’ banner protest outside Old Trafford today and, just as they did in 1999, will launch a concerted campaign to counter Glazer’s involvement.

It has already been pointed out that Glazer, while bringing success to the Tampa Bay NFL franchise, also massively raised ticket prices and it has not gone unnoticed that the Buccaneers have been unsuccessful in recent times, failing to win a single game so far this year.

Some fans are not happy at the way United is run now, even though chief executive David Gill was able to announce record £58.3m (€84.5m) profits before player trading on Monday.

The major fear is that Glazer would have to take on massive loans if he were to launch any takeover bid and the interest, added to the American’s personal profit, would come through increased ticket prices.

“The interest alone would amount to millions every year and Glazer would look to maximise profits from the club to pay back the debt,” added Spencer.

“This can only be bad news for ordinary supporters and we will do everything we can to stop him.”

Gill was intending to meet Glazer’s sons – Joel, Ed and Bryan – to discuss club strategy in light of the latest figures, although this has not yet taken place.

Instead, Gill could find himself in the uncomfortable position of having to decide whether to recommend a takeover to the club’s shareholders.

No deal could be done without the involvement of Magnier and McManus, who took their shareholding to 29% earlier in the year but are not thought to be interested in an outright takeover.

Some of the most popular United fans’ websites have been besieged by abusive messages towards Glazer and while publicly, supporters' group spokesman are maintaining a sense of reason, privately they are gearing themselves up for a very ugly battle.

“Glazer has nothing to offer but fool’s gold,” said Shareholders United spokesman Oliver Houston.

“After the turmoil of Rio and Rock of Gibraltar last season, a takeover battle would be severely damaging and Glazer would be made to pay for unleashing civil war at the club.

“The United brand could well suffer too as fans are bound to want to make their feelings clear to the PLC directors, club sponsors and anyone else seen to be colluding in selling off our heritage.

“We remain united for United.”