An agreement has been reached that could lead to an end to strike action by postal workers.
The breakthrough came late on Friday after marathon talks between Royal Mail and the Communication Workers' Union at the TUC in London.
Details are yet to be announced, but it is hoped the deal will end the dispute, which centres on pay, pensions and flexible working.
The terms reached will be considered by the union's executive on Monday.
The deal was ratified by Royal Mail boss Adam Crozier, Communication Workers' Union (CWU) general secretary Billy Hayes and his deputy Dave Ward, and TUC general secretary Brendan Barber.
If it is supported by the executive, it is likely to be put to the vote by the CWU's 130,000 members.
It is hoped the resolution will bring to an end the long-running row over Royal Mail's modernisation plans, which union officials had feared would see 40,000 jobs lost.
BBC business editor Robert Peston said the "big pillars" of management demands were in place, including pension fund reform, a pay rise this year of around 2.5% and the reform of working practices.
However, he added: "I don't think that the company has got it all its own way".
Earlier on Friday, the Royal Mail was granted an injunction to stop CWU members at sorting centres and delivery offices striking next week.
The company argued that the union had not given accurate figures for the number of staff affected by the strike - a legal requirement.
PLANNED 24-HOUR STRIKES
15 October from 1800BST: Mail sorting offices and airports
16 October from 0300BST: Deliveries and collection hubs
17 October from 1200BST: Royal Mail drivers
18 October from 1200BST: Manual data entry centres
18 October from 1400BST: Heathrow world distribution centre
The union insisted the strike was legitimate.
The CWU had announced rolling 24-hour strikes to start on Monday and end on Friday, designed to cause maximum disruption to mail services with minimal financial loss for its members.
The injunction did not apply to all parts of the Royal Mail, and in the wake of Friday's agreement it was not clear whether some groups, such as drivers, would take part in the walkouts.
Thousands of Royal Mail customers across Britain have suffered from disruption since official protests by workers began in June.
Stephen Alambritis of the Federation Of Small Businesses said: "For Britain's four million small businesses it is good news.
"They've been shelling out an extra five million pounds a day to use alternative services."
Royal Mail has insisted it needs to modernise to survive as a business in the highly competitive mail industry, while union leaders have argued that its plans have no regard for its employees.
Areas under dispute have included pay and pensions, with the CWU saying a pay rise came with unacceptable strings attached, and the Royal Mail wanting to scrap its final salary pension scheme and raise the retirement age.
Some working practices are also under dispute, such as workers being allowed to go home before their shift has ended if they have completed their designated workload
Unofficial strikes over shift times have affected deliveries in London, Glasgow, Edinburgh and Liverpool.
The wildcat protests which began on Wednesday have been called off in Scotland while some workers in London and Liverpool have not gone back to work.
Workers at all 21 delivery depots across Liverpool walked out, with CWU branch representative Mark Walsh saying staff felt they were being "being bullied into having their contract changed".
But Royal Mail condemned the mass walkouts, saying they were "wholly unacceptable" and not supported by the CWU nationally.
Postal workers in east, south-west and south-east London also went back to the picket lines over the dispute.
And staff in Edinburgh and Grangemouth walked out over pay deductions following recent official action.
Despite calls from MPs to intervene in the dispute, the government has said it will not take action.