The government has welcomed a deal which could lead to an end to strike action by postal workers.
The deal may be put to the vote by the CWU's 130,000 members
The agreement between Royal Mail and the Communication Workers' Union is still to be ratified and details have not yet been announced.
The Department for Business, Enterprise and Regulatory Reform described the development as "significant progress".
Royal Mail said unofficial strikes were continuing at about 10 delivery offices in London and 20 in Liverpool.
BBC business editor Robert Peston said it is understood that 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 but he did not think the company had "got it all its own way".
The deal was ratified by Royal Mail boss Adam Crozier, Communication Workers' Union general secretary Billy Hayes and his deputy Dave Ward, and TUC general secretary Brendan Barber.
If the terms reached after marathon talks at the TUC are supported by the union's executive on Monday, the deal 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.
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
A spokesman for the Department for Business, Enterprise and Regulatory Reform said: "We welcome this significant progress.
"Clearly it is in the interest of the customers, tax payers, postal workers and the Royal Mail for the two sides to reach a fair and lasting settlement."
John Redwood, chairman of the Conservative Economic Policy Review, said there needed to be a shake-up in the way Royal Mail operates, including introducing more private capital through the sale of shares.
He said: "There will be no winners from this primeval battle of attrition between managers and employees.
"Now a settlement is in sight, there needs to be a sharp change of direction in how the Royal Mail is run, to create a better atmosphere for employees and to win customers back."
Stephen Alambritis of the Federation Of Small Businesses said the agreement was "good news" for the UK's small firms who have spent millions on alternative services since official protests by workers began in June.
Royal Mail has been granted an injunction to stop CWU members at sorting centres and delivery offices striking next week.
But 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.
Royal Mail said about 98% of its 1,500 sites were now working normally.
It condemned the unofficial walkouts, saying they were "wholly unacceptable" and not supported by the CWU nationally.
Workers who had been staging unofficial strikes in east London and parts of Scotland have returned.
A spokesman said: "There has been a strong return to work in sites affected by wildcat action. We continue to urge a full return to work on Monday."
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 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.