It served from the start of the war and into the Battle of France, where it was found to be unreliable. They wrere all abandonded and never used again when the BEF fled northern France.
When the Infantry Tank Mk. I which was also known as "Matilda" was removed from service the Infantry Tank Mk II simply became known as the Matilda.
Matilda I's made up the majority of the British Armour in Europe when the Germans invaded France in 1939. Although the Matilda's were more heavily armoured than the German tanks, they were under gunned with only a single rifle calibre machine gun, and their top speed of 8mph made it difficult for them to manoeuvre or retreat.
As the German's pushed into France, the crews of Panzer II's discovered it was easier to cripple a Matilda than trying to penetrate it's thick armour.