This is a list of all the major variations of the Machin series of postage stamps in the United Kingdom.
Machins continued being issued after Britain's change to decimalisation, and were produced until the end of the queen's reign.
Other major variations include: NVI (or non-value indicator) Machins first appeared in 1989 in an attempt to negate the need to keep issuing new stamps after each postal rate change.
[citation needed] Machin stamps with Data Matrix barcodes were introduced in two stages, on 1 February 2022 (non-value indicators), and 4 April 2022 (other values).
On 8 February 2023, the design for the new definitive series, to be released on 4 April 2023 and featuring a portrait of Charles III by Martin Jennings, was revealed.