The union is concerned at the news group's refusal to recognise it, but said a campaign to enlist new members from Northcliffe was proving successful.

"We've had an enormous amount of interest. [The proposal to sell Northcliffe] happened in a matter of hours and the whole industry was concerned at how it just came out of the blue," said national officer Steve Sibbald.

Any sale could lead to the group being broken up.

According to press reports, venture capitalist Mecom is now out of the race, leaving six remaining bidders: Trinity Mirror with CVC; Johnston Press; and Gannett; as well as venture capitalists Cinven, Candover, and Providence Equity Partners.

Meanwhile. the union was also in talks last week with Trinity Mirror regarding job cutbacks at its Cardiff division, announced in November. Amicus said volunteers had been found to fill six redundancies at the Tidal Sidings press site in Cardiff.