The four men who had been most closely concerned wlth the direction of the joint design studies and discussions were, on the British side, Dr A. E. (later Sir Archibald) Russell, technical director of BAC's Filton Division, and Dr W. J. Strang, chief engineer of Filton Division and, on the French side, Pierre Satre and Lucien Servanty, technical director and chief engineer respectively of Sud-Aviation. Each of the four was an aeronautical engineer of international standing.