Salomon Smith Barney, the US investment bank, yesterday confirmed that it had approached Manchester United's financial advisers, HSBC, on behalf of a client who "has asked us to contact HSBC to assess the feasibility of a bid."
A spokeswoman for Salomon said it was routine for rival companies to weigh up a counter-offer in the wake of a takeover being announced.
The identity of the counter-bidder remains unclear, but a number of large companies, both inside and outside the UK, are known to be concerned that a successful bid by BSkyB, which is 40 per cent owned by Rupert Murdoch, would give the media mogul an unbeatable lead in the battle for pay-television viewers.
However, a rival bidder would struggle to justify paying a higher price than BSkyB, which already holds the rights to show live Premier League football.
Other potential bidders had been expected to wait until the Office of Fair Trading decides whether to recommend BSkyB's bid to the Monopolies and Mergers Commission before making a move.
However, the broadcasters' decision to buy 9 per cent of Manchester United shares on the stock market last Thursday may have forced its rivals' hands.
BSkyB is permitted to buy the shares for as long as the price remains below the level of its bid. Manchester United shares closed at 221.5p on Friday - almost 20p below the value of BSkyB's cash and shares offer.
Martin Edwards, Manchester United's chief executive, has committed his 14 per cent shareholding in the club to BSkyB, effectively giving the broadcaster control over a 23 per cent stake.Reuse content