Britain and Northern Ireland between 1959 and 1974. The two-class postal system was introduced in 1968, using first-class and second-class services. The Post Office opened the National Giro Bank that year.

In April 2025, Royal Mail announced that they were trialling two versions of a new solar-powered "postbox of the future" with a barcode reader and an electronically unlockable hatch to accept small parcels. By August, they decided to deploy of the red-topped version around the United Kingdom.