By September 1939 there were approximately 1,000 in service.
Defense of France
When the 1st Armored Division was sent to France in May 1940, 108 of 321 of its tanks were Light Tank Mk VIs.
Around 550 Light Tank Mk VIAs were sent to France, and only six made it out before France surrendered.
Approximately 200 Light Tank Mk VIBs were with the British Expeditionary Forces.
Some of the Light Tank Mk VIs didn't have their machine guns as they were packed separately and even shipped on a different ship.
Considered mechanically reliable so was popular in North Africa.
The Light Tank Mk VI provided the bulk of British tank strength in France and Western Desert in 1940. Used in first line units until 1942.
Used in France, Greece, Crete, Malta, Persia, and with the South Africans in Abyssinian, and Australians in Syria ( July 1941). On Malta it was used to tow wrecked aircraft off the runways.
Some in Egypt were converted to artillery observation posts. At the first siege of Tobruk the 1st Royal Tank Regiment used 16 of the Light Tank Mk VIs to deceive the Germans into thinking there were more tanks in the garrison.
Australia purchased some Light Mk VIs in 1939, and were used for training. Australian forces took over some from the British Army in the Western Desert in 1940.
Canada obtained Light Mk VIs from Britain in 1939 and used for training.