Talks aimed at averting this week's national postal strikes started today as union leaders confirmed they were considering legal action against Royal Mail's plan to take on 30,000 temporary staff.
The company said it was hiring twice as many temporary workers as normal to deal with the effects of the strike as well as the usual Christmas rush.
The Communication Workers Union said it believed the decision could be unlawful and a spokesman confirmed today it was considering taking legal action.
Union officials held fresh talks with Royal Mail bosses, with little sign of a breakthrough to a long-running dispute over pay, jobs and working conditions.
Up to 120,000 union members will strike on Thursday and Friday, threatening massive disruption to mail deliveries just weeks from Christmas.
Meanwhile 98 MPs have now signed a Commons motion supporting the union's call for peace talks to resolve the bitter dispute.
The Early Day Motion was tabled last week and is attracting growing support from mainly Labour MPs.
Billy Hayes, general secretary of the CWU, attacked the Royal Mail's decision to hire so many temporary workers as "stupid" and warned that it would inflame the dispute.
Prime Minister Gordon Brown was said be "very concerned" about the impact of a strike - particularly for Royal Mail customers.
Mr Brown's spokesman said that if the Royal Mail continued to lose business, it would be "extremely difficult" to get back
"The Prime Minister is monitoring the situation very closely," the spokesman said.
He added: "The sooner the two sides get together and sort it out, the better."
MPs from seven different political parties, including Labour, Conservative and Liberal Democrat, have signed the Early Day Motion, which also calls on the Government to do all in its power to ensure that Royal Mail "responds positively" to the union's proposal of third-party mediation.
Mr Hayes said: "We think it is absolutely right that politicians put pressure on the Government and Royal Mail to find a quick and reasonable settlement to this dispute.
"Despite recent revelations which call into question Royal Mail's intentions, the CWU remains available for talks.
"We would welcome a move to Acas, but Royal Mail has so far not committed to this without pre-conditions. Any third-party involvement needs to be on an entirely transparent basis with a joint intention of reaching an agreement."
The Early Day Motion reads: "This House welcomes the proposals put forward by the Communication Workers Union seeking to find a resolution to the current postal dispute, in particular their offer to explore the possibility of third-party mediation, and calls on the Government to do all in its power to ensure that Royal Mail responds positively to the union's proposalReuse content