In November 1941, in the Western Desert war of North Africa, Mike Sadler was a navigator with the Long Range Desert Group. Two weeks after the first and disastrous SAS operation, in which only 22 men out of 65 made it to the RV with the LRDG, Sadler navigated Paddy Mayne to the Tamet airfield, deep behind enemy lines, where Mayne and his group destroyed 24 enemy aircraft. It was the first successful SAS operation.
In the following months, during the period when the LRDG took the SAS to their targets, Sadler navigated one of the patrols involved. When David Stirling got his own jeeps, he poached Sadler from the LRDG. Sadler navigated the SAS on the first nighttime mass jeep raid on the enemy airfield at Sidi Haneish, near Fuka.
In January 1943 Sadler was with Stirling when he attempted to outflank the Germans retreating from El Alamein and connect with the British 1st Army in Tunisia. Sadly, it went wrong, and Stirling and the rest were captured. Sadler and two others got away and endured a hundred-mile desert walk to make the connection.
After D-Day, Sadler parachuted into the Morvan Mountains in Occupied France, to operate in the Forest of Orleans. He celebrated the liberation of Paris with Paddy Mayne, in Paris.