The news follows months of tussling between the two organisations and will help Royal Mail stop haemorrhaging money.
Royal Mail chief executive Adam Crozier said: "After 11 months of detailed discussion with Postcomm, we have seen real improvements to the package on the table and we are now able to agree to the new deal. We should now be able to get on and implement the modest 1p rise in postage prices we need.
"The original proposals left a 拢460m hole in Royal Mail's finances, rather than the 拢170m annual benefit from the penny price increase."
Postcomm's original proposals had been intended to limit charges for Royal Mail services such as airmail and packages in exchange for a 1p increase on stamps. However, Royal Mail chairman Allan Leighton balked at the proposals, saying this could cause the postal operator to default on loan payments to the DTI.
Consumer watchdog Postwatch warned, however, that that Postcomm may have simply bowed to pressure and passed through the price increases without proper explanation.
"This could see stamp prices rise by as much as 3p on first class and 2p on second class," it said in a statement.
The watchdog was also concerned that there had been no mention of a compensation scheme to customers for failure of the service.
The statement continued: "Under pressure from Royal Mail, Postcomm has also backed away from giving customers a proper compensation scheme.
"A mandatory scheme covering all types of failure -- lost, damaged and delayed -- was promised two years ago. Now consumers are only to be guaranteed compensation for delayed mail, and at levels lower on average than Royal Mail currently offers."
The next battle between Royal Mail and Postcomm will be over how much Royal Mail can charge rivals to use its postal network.
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