The cost of a first-class stamp will climb to £1.70, a 5p increase, while second-class stamps will be 87p, a 2p rise, when the changes come into effect on April 7.
Royal Mail, which was fined £10.5 million by regulators for failing to meet its delivery targets last year, said the spiralling prices are because of the “increasing cost of delivering mail”.
It means first-class stamps have. more than doubled in price in the last five years, after they cost just 76p in 2020.
He added that Royal Mail’s one-price-goes-anywhere so-called universal service obligation needs “urgent reform”, arguing it does not meet modern customers’ needs.
The universal service currently requires Royal Mail to deliver letters six days a week and parcels five days a week, but is under review.
Regulator Ofcom is consulting on plans to remove second-class deliveries on Saturdays and reduce them to two or three days per week.
Amanda Fergusson, chief executive of the Greeting Card Association, said:
“Here we go again. Yet again Royal Mail is asking people to keep paying more, for less, demonstrating the urgency behind our call for MPs to investigate Ofcom and Royal Mail’s plan to weaken the service.
“Our members – and their customers – know imminent plans to slash second-class services will leave them reliant on a first-class stamp at runaway prices.
“It’s time for MPs to act – they must make sure Royal Mail isn’t given carte blanche to make the postal service less reliable and unaffordable.”
It comes as Czech billionaire Daniel Kretinsky closes in on a deal to buy Royal Mail from current owner International Distribution Services.
The purchase, agreed in 2024, has now been delayed until the second quarter amid a political crisis in Romania, according to a statement earlier this week.