A fresh wave of postal strikes will go ahead from tomorrow after hopes of averting the action collapsed tonight.
Up to 120,000 members of the Communication Workers Union will walk out from 4am causing huge disruption to mail deliveries.
The strikes were confirmed despite three days of intensive talks between union leaders and Royal Mail bosses, under the chairmanship of TUC general secretary Brendan Barber.
The Royal Mail accused the union of walking away from the peace talks and condemned the new strikes.
Dave Ward, the union's deputy general secretary, said this week's talks had been the "most useful and productive" since the start of the bitter dispute over jobs, pay and modernisation.
But the company said the union was "playing havoc" with customer confidence.
Mr Ward said: "Earlier today we tabled a proposal as part of the process that reflected the progress made in negotiations over the last few days.
"Had that proposal been agreed, this would have enabled a period of calm and allowed further talks through Acas with the intention of concluding a full and final agreement.
"At this point of time, we have not had confirmation as to whether our proposal is acceptable and therefore the strikes previously announced for the next few days will take place.
"We respect the confidentiality of the process currently managed by Brendan Barber and we are not prepared to comment on the detail of those discussions or our proposal.
"This series of strikes and future strikes can still be avoided and we remain available for discussions at any time, including tonight. We remain committed to reaching an agreed resolution."
Royal Mail managing director Mark Higson thanked Mr Barber for his efforts to broker a deal and said the company was willing to talk for "as long as it takes" to resolve the dispute.
"We have repeatedly asked for a commonsense approach that allows a strike-free Christmas while we talk about the future, yet even that seems too much for the CWU to accept.
"Yesterday we were once again on the verge of a sensible agreement that would have allowed us to enter into in-depth discussions with the union over the future of Royal Mail in an atmosphere of calm, but just like last week the CWU leadership has failed to carry its own postal executive committee, which appears to be split, with London members at odds with the rest of the country and unable to reach any decision.
"We had made huge progress with the help of the TUC when the CWU came back from their executive meeting with a whole new series of demands."
Royal Mail said that after three days of intensive talks and mediation at the TUC, it was increasingly evident that the CWU leadership, the national officers and the postal executive had "very different views" on the reason for the strikes and how the dispute can be resolved.
"Royal Mail urges the union to get independent help to resolve its own internal position so that the company and the union can then get on with constructive and meaningful talks.
"The central issue remains the CWU's opposition to Royal Mail's essential modernisation plans, without which the company simply does not have a future.
"We know that we have a long way to go but our door is always open for further talks and we remain hopeful that common sense will prevail."Reuse content