A machine gunner at Sannaiyat, April 1916.

The machine-gun was one of the dominant weapons on all World War One battlefields. When established in a fixed defensive position and sited specifically to cover potential enemy attack routes it was a fearsome weapon. Infantry assaults upon such positions invariably resulted in high casualties. From a collection of 265 photographs compiled by Maj W Leith-Ross, Indian Army Staff, 1915-17. Photograph, World War One, Mesopotamia, 1916.