Households with books of non-barcoded stamps tucked away in purses, wallets and drawers are being encouraged to use them up or swap them out as the old design edges towards the end of its shelf life.

Royal Mail is asking those who may have stockpiled stamps for future use to get rid of those without the new-look barcodes as the initial deadline for using them nears.

Originally after January 31 stamps not carrying a barcode were set to be no longer valid for postage - however for the first six months until the end of July any mail carrying the retired stamps will be delivered as normal under a six-month grace period the postal service has introduced to allow people more time to get used to the changes.

Matthew Parkes, managing director of Stamps and Collectibles, said: "We don't want any of our customers to be out of pocket. In order to give our customers even more time to use up any remaining non-barcoded stamps, we introduced six-month grace period starting from the original deadline of January 31, 2023, where non-barcoded definitive stamps will still be delivered as normal.

"We continue to encourage customers to check their purses, wallets and drawers to find and use their non-barcoded Definitive stamps before the final deadline of July 31."

After this date anyone who finds an old stamp will have to call on the Royal Mail's Swap Out scheme and complete an exchange form available from Post Office branches, online and through Royal Mail customer service points.

Royal Mail says the new unique barcoded stamps, first unveiled last February, are part of plans to modernise the UK's postal system and over time help add additional security features.

Stamps eligible for the Swap Out scheme are regular 1st and 2nd Class stamps - known as everyday stamps - alongside all other values that feature the profile of the late Queen Elizabeth.

Non-barcoded Christmas stamps and other special releases with pictures on remain valid for postage and should not be submitted for the swap out.

Stamps that have already been used for postage will not be accepted through the Swap Out scheme.