The Gloster E.28/39, (also referred to as the "Gloster Whittle", "Gloster Pioneer", or "Gloster G.40") was the first British jet-engined aircraft to fly. It was designed to test the Whittle jet engine in flight, leading to the development of the Gloster Meteor.
Read more about Gloster E.28/39: Design and Development, Testing, Survivors, Operators, Specifications (Gloster E.28/39)