An official photo describing the kit of a British infantryman in 1939. Note that the gas mask ('respirator') and anti-chemical warfare cape are parts of the outfit, remnants of WW1 memories. In actual combat, and marching with full kit, the British infantryman would carry a pack known as a "valise" that contained more clothing and personal items. Officers wore the exact same uniform save for markings of their rank.
The evolution of British Army equipment through 100 years of conflict; from 1914 to 2014. Since the First World War, the British soldiers' personal kit has continuously improved to meet the new challenges of warfare. To commemorate the centenary of WW1, see how equipment capabilities through through major conflicts compare and take a look at future military technology.