Th is plaque commemorates the first test run of the jet-propelled engine at British Thomson Houston in Rugby in April 1937. 
It was unveiled in 1987 by the inventor, Sir Frank Whittle (1907-1996), to mark the 50th anniversary of the test.  It was originally on the wall of Building 86/86a at the site.
As a young man he joined the RAF and was recommended for officer training in 1926. During his training he wrote a thesis on the future development of aircraft engine design. In this he first mentioned the potential for forms of propulsion such as turbine engines.
He patented the ideas in 1930. After studying Mechanical Sciences at Cambridge, he was approached by ex RAF men, Rolf Williams and Collingwood Tinling, about exploring development of his engine. With a bank loan they incorporated as Power Jets Ltd, and work began soon after on an experimental engine at British Thomson Houston. The first test run was made on 12th April 1937. 
Vic Cox who worked as an apprentice at BT-H at the time remembers the day of the first test;
“The engine eventually started and as it gained speed the noise rose to a low shriek, increasing as the decibels and the speed became higher and higher. Everyone in the vicinity including me ran for cover and hid behind the large stanchions…Finally the howl decreased as the engine was stopped. We all came out from hiding looking more than a little scared. The hot jet had burnt all the paint off the engine shed which was in line with the exhaust”. 

Although it wasn’t entirely successful it did prove that the engine worked and was enough to gain interest from the Air Ministry. Whittle continued to be based at Brownsover Hall but testing soon moved to a disused factory in Lutterworth ending the engine testing in Rugby and British Thomson Houston’s involvement.
The plaque is one of 50 objects on display in A History of Rugby in 50 Objects at Rugby Art Gallery and Museum.