<human>:  When did the British Army first use tanks?
<bot>: The British Army first used tanks in the Battle of the Somme in 1916. The British Army had a number of armored vehicles during World War I, but they were not called tanks until after the war. The first tanks were built by the British, but they were not called tanks until after the war. The first tanks were called “landships” because they were land-based vehicles. They were called tanks because the British Army used them to attack enemy trenches.