Manchester United are so concerned about the increasing success of the green-and-gold protests that the club have effectively forbidden Sir Alex Ferguson's players from speaking about it publicly and imposed a series of other measures aimed at counteracting the kind of publicity generated by David Beckham's endorsement of the campaign.

Beckham's parting statement after United's 4-0 defeat of Milan on Wednesday, leaving the pitch with a protest scarf around his neck, is being described as "an iconic moment" by the Manchester United Supporters' Trust (Must), and senior figures at Old Trafford are worried about the significance of the most famous sportsman on the planet attaching himself to a movement aimed at deposing the ruling Glazer family.

In response the club have already:

• Banned players from discussing the campaign in the media.

• Forbidden the in-house TV station, MUTV, from referring to the rebellion and edited questions about it from broadcasts of Ferguson's press conferences.

• Ejected a supporter from the audience of an MUTV show after he refused to remove a green-and-gold scarf.

• Sacked a steward after 19 years' service for attempting to return a confiscated anti-Glazer banner to its owners.

The club has reluctantly accepted the protests will continue for as long as the Glazers are in power. David Gill, the chief executive, predicted yesterday that would be "many more" than five years.

While Beckham's latest fashion statement has been shown around the world, attracting headlines from the Boston Herald to the Times of India, MUTV has chosen to ignore what happened. Similarly Ferguson's remarks about the protests in recent weeks have been edited out when the rest of his press conferences have been aired in full. One supporter was ejected from the audience of the MUTV show, Red Cafe, when he refused to remove his green and gold scarf, security staff telling him that the colours were not allowed inside the studio, and a steward was dismissed by CES, the security firm employed by United, after attempting to return a confiscated anti-Glazer banner during the home game against Burnley.

The initial hope inside the Old Trafford boardroom was that the protests would eventually fade out but the club's attempts to quell the uprising have been unsuccessful. Protests were so widespread during the Milan game that CES had to abandon its usual policy of trying to remove the many banners criticising the Glazers and Gill.

Avram Glazer was at the game, smuggled into the stadium in a car with blacked-out windows and shadowed by a personal bodyguard, and United employees noted how calm and unmoved he seemed.

"Everyone has the right to protest and there was certainly a lot of green and gold there," Gill said at the announcement of a five-year sponsorship deal with Telekom Malaysia. "But this partnership demonstrates the strength of the club. We will be around for the length of this five-year deal and many more in addition to that."

Beckham produced the perfect publicity coup for Must and an organisation whose membership has now passed 130,000 has also been buoyed by the appointment of the Japanese investment bank Nomura to advise the alliance of wealthy United followers who are planning a takeover bid. Nomura will "coordinate and formulate the proposal to be put to the Glazer family" and Must's spokesman, Duncan Drasdo, described the appointment as "hugely significant because it will start to crystallise the offer. We've seen a lot of interest from the so-called Red Knights and Nomura's job will be to organise it."

In the meantime Must has written an open letter asking for other "United legends" to follow Beckham's lead and attach themselves to the cause. "David courageously showed his true colours," the letter says. "The movement for change is becoming unstoppable and we know that David is not alone. From Eric Cantona to Andrew Cole, former players are making their feelings known."

Ole Gunnar Solskjaer, the club's reserve coach, is a patron of the organisation and has spoken out against the Glazers in the past but the only current player to sympathise has been Patrice Evra, in response to a French journalist who asked why the United end at Wembley was decked out in green and gold. "They are the original colours of Manchester United [as Newton Heath] and the fans wear them because they love this club," Evra said. "They have their reasons for doing it and we don't think that they're crazy."

Otherwise the players have been warned to say nothing. The captain, Gary Neville, was twice asked after Wednesday's match and kept to the party line, saying only: "I'm not getting involved in that."