The National Gas Turbine Establishment (NGTE Pyestock) in Fleet, part of the Royal Aircraft Establishment (RAE), was the prime site in the UK for design and development of gas turbine and jet engines. It was created by merging the design teams of Frank Whittle's Power Jets and the RAE turbine development team run by Hayne Constant. NGTE spent most of its lifetime as a testing and development centre, both for experimental developments and to support commercial engine companies.