A deal to end the series of wildcat strikes by postal workers was agreed today, paving the way for the huge backlog of mail to be cleared.
The breakthrough came in the middle of the night following marathon talks between the Royal Mail and leaders of the Communication Workers Union (CWU).
Hopes of a deal had faded because of a number of sticking points. which held up progress.
But there was a dramatic breakthrough and both sides emerged from talks at a central London hotel just before 3.30am to announce that a deal had been reached
A joint statement said: "The Royal Mail and the CWU are both pleased to have reached an understanding that allows both parties to recommend a return to work.
"We will be talking to our people today and will now go to Acas to resolve all outstanding issues relating to pay and major change.
"We wish to apologise to customers for the huge inconvenience that has been caused and our first priority is to clear the backlog that has built up and get services back to normal."
Millions of letters have been held up by a series of wildcat strikes which started two weeks ago in west London and quickly spread across the capital and to other parts of the UK.
More than 20,000 postal workers were taking unofficial action, causing huge problems for thousands of companies.
The Royal Mail chief executive Adam Crozier unexpectedly joined the talks over the weekend in a sign of the organisation's growing desperation for a deal.
He emerged alongside CWU deputy general secretary Dave Ward to announce that a deal had been reached.
There had been optimism that an agreement would be reached yesterday but this faded as the day wore on and it was clear there were major problems.
The dispute started after a number of drivers in Southall, west London, were suspended following a row in the aftermath of an official 24-hour strike in London over allowances.
The union accused the Royal Mail of bullying and intimidating workers and of trying to force through changes to working practices.
The Royal Mail denied the charge and hit back at the union, blaming activists for spreading the dispute.
The 13,500 post boxes in London were sealed over the weekend because of the mounting backlog of undelivered mail.
Neither side would give any details of the agreement which they thrashed out.
The two sides are expected to resume negotiations later today under the auspices of the conciliation service.
In the meantime, postmen and women who have taken unofficial action were urged to return to work immediately.
The Royal Mail chairman Allan Leighton and CWU General Secretary Billy Hayes joined the talks last night and helped achieve the breakthrough, it emerged later.
Union officials and managers spent all weekend negotiating to try to find a deal and although some progress was made, the dispute looked like continuing.
At around 7pm last night Mr Crozier and Mr Ward left the central London hotel where the talks were being held and met up with Mr Leighton and Mr Hayes at a secret location.
The four men met until 2am before they returned to the talks. Later they emerged to reveal that an "understanding" had been reached.
However, further negotiations will be necessary before the dispute is finally resolved and it could take weeks to clear the massive backlog of undelivered mail.Reuse content