Peace talks will resume after the latest series of postal strikes saw millions of items of mail caught up in a huge backlog.
The Royal Mail said 25% of its delivery staff turned up for work on Saturday despite the action but the figure was disputed by the Communication Workers Union.
Officials maintained there was solid support from its 77,000 members involved in the walkout and said the public was continuing to back the workers.
Thousands of workers braved pouring rain to mount picket lines outside mail centres across the country during Saturday's third successive day of strikes in the bitter row over jobs, pay and modernisation.
The union has announced a third wave of 24 hour national stoppages next Friday, November 6 and the following Monday, November 9 involving all its 121,000 postal members although frantic efforts were continuing this weekend to try to find a peace deal.
Negotiators from the union and the company were considering a series of proposals drawn up during marathon talks last week chaired by TUC General Secretary Brendan Barber.
The two sides are due to resume negotiations tomorrow and planned to make no comment this weekend on the prospects of finding an agreement.
Billy Hayes, the union's General Secretary, said: "It is not necessary for this strike to take place and the union remains focused on reaching an agreement."
But Royal Mail Managing Director Mark Higson condemned the union for calling more strikes, warning it would "distract" effort towards making an agreement.
The Royal Mail said that the current wave of strikes had led to a backlog of 35 million items of post but the union said that figure had increased to well over 100 million.
