It is a great honour, and of considerable personal pleasure to me, to be asked to give this lecture—pleasurable for a number of reasons.

First, this is a unique occasion: this is the first time that a serving officer of the RAF has been asked to give the Sir Henry Royce Memorial Lecture and it is most appropriate that this should coincide with the 50th Anniversary Year of the RAF.

Secondly, I have always taken a great interest in aeroengines, with which I have been closely associated throughout my service career as both pilot and engineer. My early apprentice training was done on the Rolls-Royce Condor engine.