A fresh wave of postal strikes will be held next week in an escalation of the bitter Royal Mail dispute, union leaders announced today.
The Communication Workers Union (CWU) served notice of further walk-outs next Friday, 6 November and Monday 9 November.
The move came after mediators said both sides would be considering a series of proposals designed to end the "high pressure dispute" over the weekend, with further talks planned next week.
Up to 120,000 CWU members will walk out from 3am on both days causing huge disruption to mail deliveries, the union said.
Earlier, TUC General Secretary Brendan Barber, who has chaired the talks between Royal Mail managers and the CWU, said more work was needed to "finalise the terms of a possible settlement".
He told reporters it was a "difficult and complex dispute".
"Despite all the pressures of the dispute, both the CWU and the Royal Mail thought it would be right to come in again today to explore if we can resume substantive negotiations to build on the progress that was made earlier this week," he said.
"Further work is needed on both sides to finalise the terms of a possible settlement."
He said both sides would consider "a number of proposals" over the weekend and consult with colleagues "with a view to returning to the TUC for further negotiations early next week".
Mr Barber acknowledged the intense media interest in the "high pressure dispute" but said it was not helpful for details of negotiation positions and possible solutions to be discussed in the media.
He added: "Everyone involved in these talks knows how damaging it would be if an agreement is not achieved.
"In my judgment too, both parties have a genuine desire to build a better relationship going forward, to transform and modernise Royal Mail in the interests of the service and the workforce too.
"I hope that these talks, which will be resumed next week, will be able to make a breakthrough to an agreement that can provide a more positive way forward."
A Royal Mail spokeswoman said she could not give an estimate of how long it will take to clear the 35 million items of mail delayed by this week's strikes.
But she added the company "continues to do all it reasonably and legally can to clear mail delayed by the CWU's strikes and get the post to our customers as soon as possible".
"Virtually all" delays to the 30 million items of mail caught up in last week's strikes have now been cleared, she said.
The third wave of national strikes next week will increase tensions amid fears of huge disruption to Christmas post.
The strikes, which ran for a second day today, will also continue tomorrow in the long-running row over jobs, pay and modernisation.
Earlier, the union's general secretary Billy Hayes said there was "every prospect" industrial action will be stepped up.
He added the union was still considering whether to take legal action over Royal Mail's move to hire 30,000 agency workers to deal with the backlog of mail caused by the strike as well as the Christmas rush.
Mr Hayes said: "We will be upping the dispute. We will not be scaling it down. There is every prospect that we will increase the action and we could be looking at longer strikes."
Royal Mail managing director Mark Higson said yesterday the sticking point to the dispute was resistance to modernisation in certain parts of the country, adding that agreement had been reached in many areas.
Royal Mail condemned the CWU's decision as "destructive".
Mr Higson said: "The CWU claims to want a resolution to this dispute yet they know that more strike action will distract from the important discussions that need to take place and to which we at Royal Mail are committed.
"Royal Mail will, of course, continue to honour Brendan Barber's request today not to discuss those talks.
"The CWU's irresponsible behaviour underlines just how muddled and confused the thinking of the union is - and how little it really cares about customers or the future of the UK postal service.
"Thanks to the efforts of all our people who continue to work, to the dedication of managers and to the help of up to 30,000 fully vetted temporary workers engaged by Royal Mail, we will be able to limit the effect of the current strikes and expect to get any delayed mail to our customers by early next week, well ahead of the CWU's next planned action."Reuse content