“no rules except one: kill or be killed…” He could have killed you five hundred different ways at the same time.

“Get tough, get down in the gutter, win at all costs… I teach what is called ‘Gutter Fighting.’ There’s no fair play, no rules except one: kill or be killed.”
William Fairbairn was a British Major, police officer and exponent of hand-to-hand combat method, the close combat, for the Shanghai Police between the world wars, and allied special forces in World War II. He developed his own fighting system known as Defendu, as well as other weapons tactics. Notably, this included innovative pistol shooting techniques and the development of the Fairbairn-Sykes Fighting Knife.
The television series Secrets of War suggested him as a possible inspiration for Q branch in James Bond.
Fairbairn served with the Royal Marine Light Infantry starting in 1901, and joined the Shanghai Municipal Police (SMP) in 1907. He served in one of the red light districts. During his service with the International Police in Shanghai, Fairbairn reportedly engaged in hundreds of street fights in the course of his duties over a twenty-year career, where he organised and headed a special anti-riot squad. Much of his body, arms, legs, torso, even the palms of his hands, was covered with scars from knife wounds from those fights. Fairbairn later created, organised and trained a special anti-riot squad for the Shanghai police force, as well as developing numerous firearms training courses and items of police equipment, including a special metal-lined bulletproof vest designed to stop high-velocity bullets from the 7.63x25mm Mauser pistol.
During World War II, he was recruited by the British Secret Service as an Army officer, where he was given the nickname “Dangerous Dan”. Together with fellow close-combat instructor Eric Sykes, Fairbairn was commissioned on the General List in 1941. He trained British, American and Canadian Commando and No. 2 Dutch Troop 10th Inter-Allied Commando forces, along with Ranger candidates in close-combat, pistol-shooting and knife-fighting techniques.




Fairbairn emphasised the necessity of forgetting any idea of gentlemanly conduct or fighting fair: “Get tough, get down in the gutter, win at all costs… I teach what is called ‘Gutter Fighting.’ There’s no fair play, no rules except one: kill or be killed,” he declared. One of his pupils was Raymond Westerling, who fought behind enemy lines in Burma and Indonesia.
Fairbairn’s most famous invention however, was the combat knife he developed with his friend Eric Sykes, a weapon creatively known as the Fairbairn-Sykes Knife and is also known as the ‘commando knife’.
Developed just prior to World War II, this narrow, 6.5-inch blade was designed specifically for stabbing between the ribs and into the soft tender parts of whoever is currently trying to kill you. Sharp enough to pierce and kill through the thickest clothing worn by any army in the world – a Soviet greatcoat (remember, the Soviets weren’t even Britain’s enemies at this point) – this weapon also featured a tapered handle that allowed it to be comfortably held and effectively wielded from a number of different hand grip positions.
The weapon was so revolutionary that it was immediately assimilated into the British Army. It became the standard-issue combat knife of the SAS, the Royal Commandos, and the United States Marine Corps Raiders during World War II.  The Fairbairn-Sykes knife is strongly associated with the British commandos and the US Office of Strategic Services (OSS) and Marine Raiders (who based their issued knife on the Fairbairn-Sykes), among other special forces / clandestine / raiding units. It features in the insignia of the British Royal Marines, the Belgian Commandos, the Dutch Commando Corps, founded in the UK during World War II, the Australian 1st Commando Regiment and 2nd Commando Regiment, and the United States Army Rangers, both founded with the help of the British Commandos. A solid gold Fairbairn-Sykes fighting knife is part of the commandos’ memorial at Westminster Abbey.






http://www.warhistoryonline.com/war-articles/no-rules-except-one-kill-or-be-killed-he-could-have-killed-you-five-hundred-different-ways-at-the-same-time.html


Much more to read on the link.
We taught this method to the soft yanks also.
Its always the Brits that devise the best methods it seems.