Meanwhile Interpublic Group, the US advertising giant rumoured to be stalking Manchester United, denied it was the mystery bidder.
In a statement issued through Octagon, its sports marketing and entertainment arm, IPG said: "We can confirm that neither Octagon nor IPG have at any time made a bid for Manchester United ... and that we have no plans to make a bid."
Shortly afterwards Salomon Smith Barney, the US investment bank, issued a statement saying it was "not currently acting on any offer for Manchester United either as principal or on behalf of any client".
The Salomon statement, which was released to the Stock Exchange after the close of trading, appeared to contradict the bank's admission last Sunday that it had been asked to speak to Manchester United's financial adviser, HSBC, on behalf of a client in order to assess the feasibility of a bid.
Not to be outdone, British Sky Broadcasting, the satellite broadcaster which unleashed the takeover frenzy last week when it launched a pounds 623.4m offer for Manchester United, issued its own statement.
BSkyB denied newspaper reports that Rupert Murdoch's News Corporation, which owns 40 per cent of the broadcaster, was attempting to buy players on Manchester United's behalf.
"BSkyB does not own a football club. We are bidding for a club. BSkyB does not pick the team. It is the job of the board of Manchester United to decide whether to buy new players," the statement said.