Sheets of three trials of the Machin Head, produced in 1997, have just come to light a full half-century after the philatelic premiere of Arnold Machinís iconic plaster bust of Queen Elizabeth II.

Introduced in 1967, the Machin definitives were first printed in lithography in 1980 as Royal Mail expanded its range of suppliers. By the mid-1990s it had decided that all the standard definitives should be printed in gravure. The then current printer, the House of Questa, based in South London, did not have gravure capability. Thus Royal Mail was authorized to approach Helio Courvoisier SA of Switzerland (noted for the high quality of its photogravure work), probably with a view to subcontracting the gravure printing.

The fully finished, perforated and gummed non-denominated trials were undertaken on 20 October 1997 in sheets of 200, and then trimmed into panes of 100 with the Courvoisier imprint along the vertical margins. They exist in three colors: deep green (as used for the 2p), light grey (as used at the time for the 29p), and flame (as used for 1st [first] class). Using its work on the 1993-99 "Birds" definitives of Kenya, Courvoisier printed these trials on coated paper without phosphor bands. Perforated 15 x 14, the familar stamp image is slightly smaller than that of the Machin definitives in use at the time.

Stanley Gibbons has confirmed that these unique stamps will be included in the next Great Britain Specialized Stamp Catalogue, Volume 4, Part 2 (Queen Elizabeth II Decimal Definitive Issues).

A set of the panes are being donated to the National Postal Museum in London. Special thanks to Allan Grant at Rush Stamps for making this possible.

You can view this discovery set of panes that will be on display at the Spring STAMPEX 2017 on 15-18 February, at The Business Design Centre, Islington, London, Stand 18.