This is a set of First World War body armour, used by the British Army. It has curved metal plates for the chest and the back, and was supposed to protect snipers and other vulnerable soldiers by stopping or deflecting bullets. Unfortunately, the metal is very thin, and probably would not have stopped a direct hit. Also, the metal curves in to the middle, so any bullet hitting in the centre of the armour would have been deflected inwards!
This set belonged to Private A. W. Tunkiss of the 1/8th Battalion, Worcestershire Regiment. He used it in France in 1916. He was wounded in action on the 5th November 1916, and discharged from the Army the following March .