There were hopes last night of a breakthrough in the postal dispute after the two sides agreed to hold talks.
The Trades Union Congress (TUC) said yesterday it had invited the Royal Mail and the Communication Workers Union (CWU) to the table tomorrow and that both had accepted. The union umbrella body was hopeful of an end to the wrangling that led to two one-day strikes last week.
"I have had a number of conversations with [the TUC's General Secretary] Brendan Barber over the last few days and I'm very pleased we seem to have found a sensible and positive way forward," the Royal Mail chief executive, Adam Crozier, said yesterday, as workers began clearing the backlog of 30 million letters and parcels.
The CWU had planned another series of strikes to start this Thursday, and the dispute was expected to escalate further after it emerged that the trade union Unite has written to 10,000 Royal Mail managers saying it supported the strike action.
The letter said: "It is our wish to give CWU all possible support, within the law, to help ensure a satisfactory settlement. We would ask you to ensure that you undertake no work beyond your normal duties that would assist management in its efforts to undermine legitimate industrial action."
The GMB union also waded into the dispute, describing plans by the Royal Mail to hire 30,000 casual workers to break the strike as "illegal" and setting up a hotline for members of the public to report agencies that were supplying staff. The Royal Mail has strongly denied that its move to hire 30,000 agency workers was illegal.
This week's coming strikes are due to involve 43,700 staff across the UK in mail centres, delivery units, drivers and garage staff on Thursday; 400 workers in Plymouth, Stockport and Stoke who deal with poorly addressed mail on Friday; and 77,000 delivery and collection workers on Saturday.
Mr Crozier will give his first interview since the strikes started when he appears on the BBC's Andrew Marr Show this morning.
The TUC added in a statement yesterday: "Royal Mail and the CWU have in recent days been in contact with the TUC over the current dispute. As a result, both Royal Mail and the CWU have accepted an invitation from TUC General Secretary Brendan Barber to talks on Monday."
A CWU spokesman said: "The CWU has been calling for talks and is pleased that Royal Mail has now agreed to return to negotiations."