LONDON — An attempt by the owner of U.K. broadcaster Channel 5, Northern & Shell, to sell the network appears to have faltered as reports circulated Thursday that one of the leading contenders to acquire the TV group, Discovery Communications, had withdrawn from the bidding process.

Discovery was reported to have tabled a joint bid with Rupert Murdoch-controlled satcaster BSkyB worth £350 million ($587 million). Under the deal, Discovery would have taken a 70% stake and BSkyB would have nabbed the remaining 30%. BSkyB would have added Channel 5’s advertising inventory to its own sales operation.

According to the Financial Times on Thursday, Northern & Shell had held out for a higher price, but Discovery and BSkyB refused to up their offer. It now looks like Northern & Shell’s stance has prompted Discovery to walk away from the table.

A spokesperson at Northern & Shell declined to comment on the latest reports, but referred to a statement earlier this week, when she had said the company had “a number of bids as expected, which we will evaluate with our advisers over the next few days.”

Other bidders are thought to include Viacom and Nordic TV group Modern Times Group. Northern & Shell had initially sought more than £700 million ($1.18 billion) for Channel 5.

Northern & Shell is owned by media mogul Richard Desmond, who is known to be a tough negotiator. If the Channel 5 sale fails to go ahead, Plan B may be to launch an IPO for the network.

Desmond bought Channel 5 from RTL Group for £104 million ($174 million) three years ago, and has embarked on a ruthless cost-cutting exercise. The network airs a broad range of Hollywood series and movies.