It was formed in France on 13 July 1915, under the command of Lieutenant-General Charles Monro.

[2] This remained the case until March 1916, when the Tenth Army was moved to take part in the Battle of Verdun because of French losses and the Fourth Army was formed in preparation for the Battle of the Somme.

However, due to various Allied deception efforts, German intelligence over-estimated the number of Allied forces based within the UK by the start of 1944.

While there was no specific deception effort to create the Third Army, German intelligence believed that one had been formed from Northern Command.

This article about a specific British military unit is a stub.