Supersonic transport M wing design at the rear with delta wing test model in the foreground circa Fairey Delta 2 era.
The W-wing Harrier model, on display at the FAST Museum, was adapted by DERA Farnborough in the early 1990s (in collaboration with BAe) to test the suitability of an M or W wing for use on a STOVL aircraft.
Note Gloster Javelin wooden wind tunnel model top right.
Farnborough FAST Museum Feb 2020