 The Special Air Service ( SAS ) is a regiment of the British Army and part of the United Kingdom 's special forces . The regiment was formed by Colonel David Stirling in Africa in 1941 , at the height of the Second World War . Its original role was to penetrate enemy lines and strike at airfields and supply lines deep in enemy territory , first in North Africa and later around the Mediterranean and in occupied Europe . Stirling established the principle of using small teams , usually of just four men , to carry out raids — having realised that a four @-@ man team could sometimes prove much more effective than a unit of hundreds of soldiers . 
