In his book, The First Commando Knives, Kelley Yeaton documents the development of the Fairbairn/Sykes commando knife through the correspondences he maintained with his brother, Sam Yeaton. Sam Yeaton was a marine stationed in the 30's, with Shanghai Municipal Police, a multinational contingent, under the direction of Superintendent W.E. Fairbairn and helped the latter in the development of the commando knife.
The following is a letter from Sam Yeaton to the author regarding Fairbairn's self-defense/personal combat approach. More interesting than anything else is the implications of what were described. And these implications can only be discovered through one's own training...
"This man Fairbairn is beyond the shadow of a doubt the greatest of the 'the greatest of them all.' I've had about 12 hours of conferences with him and done a couple of hours work on the mats. His stuff is not jiu-jitsu or judo -- he gave us an exhibition of judo using five men, two third degree black belts, two second, and one first, to prove it. He uses some of their falls and a few holds, but not more than 20% of it and most with variations. It's not Chinese boxing, of which 80% is mere ritual. It's a collection of all the known methods of dirty fighting and it will beat them all. He knows it will, he's done it. Judo is too clean... on every hold a judo man's eyes and testicles are vulnerable. But it is awful fast, still, it's not as fast as boxing. We proved that, and to the Japs, at that. Given men of equal speed, it's the man who is not surprised by the other's method of attack who will win. We put Sam Taxis who boxes featherweight now against a third degree judo man [the punches not to be delivered and the throws not to be carried out] and it was a draw. But we had a man hold up his hands as a target and Sammy Taxis put a one-two on it while a man stood beside the hand and tried to grab his hands. All they got was his necktie... The remarkable thing about Fairbairn is that although he damn near does know it all, he doesn't seem to think he does. IF you've got an idea, he'll not only listen to you and point out what's wrong, if anything, but he'll admit if it's new to him and as good or better than his own current methods."
Following his tenure with the Shanghai Municipal Police, on loan from the British to the US, Fairbairn trained the Office of Strategic Services (OSS) operatives in knife fighting techiniques during WWII. He also trained the hand to hand combat instructors for the British military. He wrote "Get Tough", a manual of fighting to prepare the British populace for an anticipated invasion by the German forces.