This is a Notable Operational milestone.
This was the first outdoor flight of the helicopter. The aircraft left the ground by a few feet but immediately toppled sideways. Mr R. Graham was the pilot, who was unhurt in the incident. The aircraft was a 2-blade machine driven by propellers at the tips (see image), with 2 other 'blades' seemingly used for some some form of control.
The aircraft had been designed by Louis Brennan in response to a competition organized by the British Air Ministry. It is blieved that the aircraft had flown indoors as early as 1922.
A detailed description of the design and development of this aircraft can be found in the following reference,
"A Chronicle of Early British Rotorcraft", J. Gordon Leishman, Presented at the 60th Annual Forum and Technology Display of the American Helicopter Society International, Baltimore, MD, June 7–11, 2004