In addition to the permanent divisions, the Indian Army also formed a number of independent brigades. As part of the Southern Army the Aden Brigade was stationed in the Aden Protectorate on the strategically important naval route from Europe to India, where there was limited fighting. The Bannu Brigade, the Derajat Brigade and the Kohat Brigade were all part of the Northern Army and they were deployed along the North West Frontier. On 12 May 1918, the Bannu and Derajat brigades were designated as the Waziristan Field Force under the command General G W Baynon. The South Persia Brigade was formed in 1915 at the start of the Persian Campaign to protect the Anglo–Persian oil installations in south Persia and the Persian Gulf.