There’s a lot for Manchester United to discuss on their way to Southhampton this morning. The most informed member of the squad may well be Rio Ferdinand. Last Wednesday 30 men in balaclavas turned up at his home in the footballers’ village of Alderley Edge, Cheshire. They had a message to deliver: don’t co-operate with Malcolm Glazer, the Florida billionaire who last week seized control of the club. Having made their point, the men left peacefully after a brief chat. It’s not the last chat they are planning.

They came from the so-called Manchester Education Committee (MEC), a hardcore group of United fans who have pledged to do anything they can to break Glazer’s control of the club.

The owner of the Tampa Bay Buccaneers has been stalking United for more than two years. Last Wednesday he bagged his prize, after buying out Irish racehorse barons John Magnier and JP McManus to become the majority shareholder. But while Glazer may have won in the boardroom, the MEC is determined he will lose on the pitch.

It was planning its strategy this weekend. Options include disrupting next week’s FA Cup final and rioting at United’s European games next season in order to get the club thrown out of competitions.

“This is war. The MEC won’t be happy until Glazer has gone,” a source said. Directors are likely to be the first target of the civil-disruption campaign. The MEC wants David Gill, chief executive, to resign.

The MEC may represent a militant minority but many ordinary fans, too, are angry about the takeover, fearing higher ticket prices and a wholesale sell-out to corporate sponsors. Last week they were burning season-ticket renewal forms and threatening to boycott the club and its merchandise. The question now is how far they will go to express their rage.

Fans have targeted Glazer’s advisers throughout the bid. His banker, NM Rothschild, has security guards stationed at its Manchester offices; there are rumours that fans tried to hack into the bank’s computers.

Representatives of Glazer’s former bank, JP Morgan, were attacked at a meeting of pension-fund managers in Manchester last week.

There is a feeling of siege at the club. On Thursday evening, as fans protested at Old Trafford, Gill telephoned all United’s commercial partners, including shirt sponsor Vodafone and kit-maker Nike, to reassure them their businesses would not be damaged by the Glazer takeover. The sponsors themselves seemed less sure.

“It’s potentially disastrous for United,” said one sponsor’s executive. “Our involvement with United is predicated on the team’s success on the pitch, but the disruption that this is going to cause will make it very difficult for the team in the foreseeable future. And any boycott of our products by fans would entirely defeat the logic of our partnership in the club.”

Others are more sanguine. Glazer faced a similar, if less hostile, reaction from fans when he bought the Tampa Bay Bucs in 1995. Success on the field defused the criticism, although he has remained a controversial figure in Florida and once threatened to move the club unless the city paid for a new stadium.

Vodafone denied it had serious concerns about the take-over, despite repeated threats by fans to boycott United’s commercial partners. And one long-time United director said the protests would soon die down: “We had the same thing when there was a bid from Rupert Murdoch (chairman of News Corp, ultimate parent of The Sunday Times). We had the same thing when we went public. They’d be like this if anyone bid. It’s just 1% of the fans who feel like this. Glazer has made two big mistakes; first he’s been badly advised and knows nothing about football, and second he’s so ugly.”

AT 9pm on Wednesday a limousine pulled into fashionable Hamilton Place in central London. Outside Les Ambassadeurs, the casino and restaurant frequented by United manager Sir Alex Ferguson, the driver dropped off two very happy Irishmen, Magnier and McManus. The pair were in the mood to celebrate. Hours earlier, they had clinched a deal to end the most tempestuous investment of their careers.