The device in question appears to be an Armstrong Whitworth guided missile test vehicle. It was apparently shown in public for the first time at the 1953 edition of the Farnborough air Show. That vehicle might have been tested earlier than that however.
The source of the photo seems to be an article entitled "History, Problems, and Status of Guided Missiles" published in the November 1955 issue of
Jet Propulsion, the monthly magazine of the American Rocket Society.
The article appears to be accessible via
https://archive.org/details/sim_american-rocket-society-ars-journal_1955-11_25_11/page/620/mode/2up?q="british+research+missiles"
Someone with access can also scroll through it at
https://arc.aiaa.org/doi/10.2514/8.6834