The printers, many of which were selected more than two years ago, were charged with producing tens of thousands of 96-stamp sheets for regions in England, Scotland and Northern Ireland.

With LOCOG, the Games’ organising body, preparing to disband at the end of December and Royal Mail managing director of stamps and collectibles Andrew Hammond visiting the printers to thank them in person, they have been given the green light to reveal their identities and talk of their experiences.

The no-longer ‘secret six’ are Wimbledon’s Aquatint BSC, covering London and the Southeast; Swindon’s Acorn Press for the Southwest; Norfolk’s Breckland Print covering East England; Crescent Press in Solihull for the Midlands; Allander Print in Edinburgh, which was responsible for Scotland and Northern Ireland; and Lancashire-based B&D Print Services, which covered the North of England.

The project, managed by Royal Mail and St Ives Management Services, saw each printer sent digital files by Royal Mail’s in-house designers of stamps bearing images of gold-winning Team GB athletes just minutes after the medals had been awarded.

Each of the six printers then had to overprint the stamp images on pre-prepared base sheets, often having to work though the night in order to meet an early-morning deadline, varying from 4.30am to 7am, when Post Office couriers would pick up the stamps so that they could be on sales in Post Offices within 24 hours of gold wins.

Graeme Thurman, sales director of Crescent Press, said: "Within one hour of a British athlete winning a gold medal, we receive the artwork. The stamps had to be printed on all sites within an hour of that, then trimmed and collated into the unique gold medal bags and ready for the Royal Mail drivers to collect at 7am the following morning, so that they could go on sale at 9am."

Read this week’s edition of PrintWeek for a Briefing focused on Royal Mail’s project and the involvement of the ‘secret six’.