It has generally been accepted that Stirling came up with the idea sometime in July 1941, though the actual founding date has remained unknown.

But documents recovered by the author and service records show the first detachment was formed on August 28 - the day The Originals first assembled at their makeshift camp at Kabrit in Egypt.

The roll of honour has also confirmed the identities and details of six soldiers from the SAS and seven from the LRDG who were either unknown, or until now had only been suspected of being members.

Poor paperwork, secrecy, spelling mistakes and wartime confusion meant that some casualties were only recorded according to their parent unit, with no mention of them being attached to the SAS.

In some cases the research has put names to casualties described in operational reports, but whose identities were not known.

As a result some new names have already been added to the SAS official memorials in Hereford and Stirling.

The author said his research had also recognised 21 French and Greek nationals killed while officially attached to the British SAS.

“This is the first time that illustrated biographical entries have been written for each wartime casualty of the SAS and LRDG, with new casualties having been identified,” the author told the Sunday Telegraph.