The Derby Scheme was introduced during World War I in Britain in the autumn of 1915 by Herbert Kitchener's new Director General of Recruiting, Edward Stanley, 17th Earl of Derby (1865–1948), after which it was named. The scheme would demonstrate whether British manpower goals could be met by volunteers only, or if conscription was necessary.
Derby required each eligible man aged 18 to 41 who was not in a "starred" (essential) occupation to make a public declaration. When the scheme was announced, many men went to the recruiting office without waiting to be "fetched". It was an enormous enterprise. Each eligible man’s blue card from the recently completed National Register was copied onto a pink card, which was sent to his local constituency's Parliamentary Recruiting Committee.
The Committees appointed canvassers who were "tactful and influential men" not liable for service; many were experienced political agents. Discharged veterans and fathers of serving men proved most effective. A few canvassers threatened rather than cajoled. Women were not permitted to canvas but did track men who had moved,  although there were exceptions. Each man was handed a letter from Derby explaining the programme, emphasising that they were in "… a country fighting, as ours is, for its very existence ...".  Face to face with the canvasser, each man announced whether or not he would attest to join the forces; no one was permitted to speak for him.
Those who attested promised to go to the recruiting office within 48 hours; many were accompanied there immediately. If found fit, they were sworn in and paid a signing bonus of 2s 9d. The following day they were transferred to Army Reserve B. A khaki armband bearing the Royal Crown was to be provided to all who had enlisted or who had been rejected, as well as to starred and discharged men (but they were no longer issued or worn once compulsion was introduced). The enlistee’s data was copied onto a new white card which was used to assign him to a married or unmarried age group. There were 46 groups. They were promised that only entire groups would be called for active service and they would have 14 days’ advance notice. Single men's groups would be called before married; any who wed after the day the Scheme began were classified as single. Married men were promised that their groups would not be called if too few single men attested, unless conscription was introduced.
The survey was done in November and December 1915. It obtained 318,553 medically fit single men. However, 38 per cent of single men and 54 per cent of married men had publicly refused to enlist. This left the government short, and conscription was introduced in January 1916.
- "Recruiting Supplement" The Times (London) Special Supplement, 3 November 1915
- Manchester Guardian October and November 1915
- The Times (London) Special Supplement, 3 November 1915 p. 3
- PRO CAB 37/140/1