The tank first saw combat use at the Battle of the Somme in 1916. British Mark I tanks entered action on 15 September 1916 during the Battle of Flers-Courcelette, a phase of the wider Somme Offensive. Their intended roles included crossing trenches, crushing barbed wire and helping infantry attack German defensive positions.
The debut was experimental and difficult. Forty-nine tanks had been assigned to the operation, but only thirty-two reached the starting line, and many broke down or became stuck in shell-damaged terrain. Nevertheless, the machines demonstrated that armoured vehicles could cross obstacles that stopped ordinary infantry and could threaten machine-gun positions.
The Somme was not a decisive tank victory. The vehicles were slow, mechanically unreliable and difficult to coordinate with infantry and artillery. Their first large-scale and more effective employment came later at Cambrai in November 1917. Another common mix-up is calling machine guns the answer: machine guns had been used extensively before 1916, whereas tanks were the new weapon making their combat debut at the Somme.