His secondment became a permanent transfer on August 1923 ( backdated to June 1919 ) .
From 13 January 1922 Crocker was seconded to the Royal Tank Corps ( later the Royal Tank Regiment ) to specialise in the then new field of armoured warfare .
Crocker 's secondment became a permanent transfer on August 1923 ( backdated to June 1919 ) .
From 13 January 1922 Crocker was seconded to the Royal Tank Corps ( later the Royal Tank Regiment ) to specialise in the then new field of armoured warfare .