In September 1939, Major General Martel took command of the 50th Northumbrian Motorized Division of the Territorial Army, which fought fiercely on the Meuse against German Generalmajor (U.S. equiv. brigadier general) Erwin Rommel's 7th Panzer Division; Martel's forces temporarily checked the panzer advance to the Channel, until their limited numbers compelled Martel to withdraw. In December 1940, after returning to Britain, Martel became commander of the Royal Armoured Corps, which initially controlled all British armored forces, and in 1942, he was promoted to lieutenant general. He resented the creation of the British Tank Parliament in 1942, a grouping of divisional commanders and tank experts that he felt weakened his authority. In autumn of that year, during his absence in Burma and India, the position of commander, Royal Armoured Corps, was abolished.
Martel subsequently spent a frustrating year heading the British military mission in Moscow. In 1944, he lost an eye during a bombing raid on London, and he was invalided out the army in 1945. In retirement, Martel wrote his memoirs and several often controversial books on armored warfare and relations with the Soviet Union, including Our Armoured Forces (1945), The Russian Outlook (1949), and East versus West (1952). He died in Camberley on 3 September 1958.
Clay, Ewart W. The Path of the 50th Northumbrian Division in the Second World War, 1939–1945. Aldershot, UK: British Army, 1950.; Larson, Robert H. The British Army and the Theory of Armored Warfare, 1918–1940. Newark: University of Delaware Press, 1984.; Martel, Sir Giffard. An Outspoken Soldier: His Views and Memoirs. London: Sifton Praed, 1949.; Wright, Patrick. Tank: The Progress of a Monstrous War Machine. New York: Viking, 2002.