A 2p rise has come into effect on first and second-class stamps, making them 67p and 58p respectively.
Royal Mail said that the increase was necessary to maintain the universal postal service.
The rise in the price of stamps has outstripped inflation. If the price had risen in line with inflation since the late 1980s, a first-class stamp would cost 31p.
'We understand how hard it is for many companies in the current economic environment,' said a Royal Mail spokesperson. 'For that reason, we have considered any changes very carefully and have sought to minimise their impact on our customers. We also want to reiterate our ambition to remain a trusted and valued business partner and being the best delivery and mail business for your needs.'
Meanwhile, Royal Mail said today that new data has shown an increasing trend for Easter greetings cards.
While fewer people might be sending letters these days, research from the Greeting Card Association indicated that seasonal cards are still being delivered by post.
In 2016, 8.5m Easter cards were sold, marking a 13 per cent increase on the previous year.
A Royal Mail spokesperson said: “The UK loves sending greeting cards, and Easter is no exception. Even in a world of emails and social media, Easter cards are becoming increasingly popular, both as a means of celebrating the religious festival and simply keeping in touch with friends and relatives. We all like to receive a card in the post, and a personal card is a perfect way to wish someone well this Easter.”