Why was the Somme offensive launched in 1916?

The battle of Verdun was a major battle that started in February 1916 and didn’t end until December. I believe this was the most important reason because the Somme was originally supposed to be a French campaign with British support but because of the staggering numbers of loses the French were taking at Verdun they could not have as much of a say. Also if the Germans managed to beat the French at the battle of Verdun then it would leave Britain extremely vulnerable to attack from the German forces which put them in a good position to give terms for peace treaties and Britain could not let this happen.  This links me into my next point of political pressure. Because of the battle of Verdun the British government was being put under a lot of pressure to do something in retaliation. With this yet more political pressure was added by the failed attempt at Gallipoli to take turkey (A German ally.) out of the war. Also the naval battle of Jutland was only seen as a draw. This was because although the German Navy had been defeated the British still lost more ships. All the failed battles mentioned build up to the fact that the British government needed to show the people of Britain that we did have a chance in the war. The last thing they needed was the collapse of trust inside the country.

Another reason for the attack at the Somme was the fact that the stalemate between the trenches at the time needed to be broken. The government saw it as the perfect place to punch a whole through the enemy lines and destroy their trenches. This would leave German territory defenseless against the British, French and Russian onslaught. This would make us more in the position to dictate harsher peace treaties.