Common among snipers the world over today, the ghillie suit or bush suit, traces its origin to Scottish gamekeepers with a Scotland-raised yeoman regiment, the Lovat Scouts, using them for the first time in modern combat in the Boer War.
These Highlanders, drawn largely from outdoorsmen, were described as “half wolf and half jackrabbit” in their tactics when down in the veldt and the suit draws its name from the Gaelic faerie Gille Dubh, a forest character clad in moss and leaves that hides among the trees. The use of “scrim” often from repurposed potato sacks, helped break up their outline.
What is scrim?
Scrim is nothing but a basic fabric that has a light, almost gauzy weave to it. It’s used in bookbinding (that woven fabric in the back of hardcover books), theatre and photography (to reflect light), and in simple industrial applications like making burlap sacks.

(H 10707) A camouflage suit for a sniper. Copyright: © IWM. Original Source: http://www.iwm.org.uk/collections/item/object/205215212
The suits became widespread in sniper use in the Great War. Take this superb example in the IWM under review:

“First World War period British Army sniper’s camouflage robe. Many British Army snipers were trained by former Highland gamekeepers and deer stalkers of the Lovat Scouts, who gave extensive guidance regarding their skills of personal camouflage and concealment. As a result, many items of clothing were adopted on the Western Front, either improvised or officially produced, including mittens, gaiters, and robes” Copyright: © IWM. Original Source: http://www.iwm.org.uk/collections/item/object/30097861
Here is another.

“Robe loose-shaped single-breasted robe, made of linen, complete with a fitted hood that incorporates a face mask with apertures for the mouth and eyes. The smock is dabbed and smeared with various shades of paint to achieve a random (disruptive) camouflage finish.” Original Source: http://www.iwm.org.uk/collections/item/object/30100483
And a third:

“Smock: loose-shaped single-breasted robe, made of canvas, complete with a fitted hood that incorporates a face mask with openings for the mouth and eyes. The smock is painted in colors of various shades to achieve a random camouflage finish and, additionally, has tufts of dried organic vegetation sewn to break up the outline.” Copyright: © IWM. Original Source: http://www.iwm.org.uk/collections/item/object/30092440
When the Second World War came in 1939, the Brits fell back on what worked.

“Experiments in camouflage, 1940. One figure is trying on the upper portion of a prototype sniper suit. He is being watched by a man wearing Khaki and smoking a pipe, who is holding the suit trousers. On the floor behind them are some pots of paint and another suit hung on a mannequin. There are more sketches of the suit in the upper right corner of the page.” Copyright: © IWM. Original Source: http://www.iwm.org.uk/collections/item/object/38898

A Camouflaged Sniper watching his Target, Llanberis, North Wales (Art.IWM ART LD 3422)”A head and shoulders depiction of a British infantry sniper in training in Wales. The sniper is shown wearing camouflaged kit and black face paint, aiming his rifle at a distant target.” Copyright: © IWM. Original Source: http://www.iwm.org.uk/collections/item/object/21861

British Snipers on the Island of Ubbea near Khakio : 10th Infantry Brigade (Art.IWM ART LD 5040) image: In the foreground three carefully camouflaged British snipers wearing camouflaged smocks have positioned themselves
amongst the rocks and vegetation of a hill side. They appear to be overlooking a road that winds through a hilly coastal country. The sea and a neighboring island are visible in the top right of the composition. Copyright: © IWM. Original Source: http://www.iwm.org.uk/collections/item/object/5318

Normandy Campaign (B 8177) A sniper demonstrates his camouflage at a sniper school in a French village, 27 July 1944. Copyright: © IWM. Original Source: http://www.iwm.org.uk/collections/item/object/205202430
The practice continues across MoD today, using low-IR fabric to keep down detection by modern optics, because if it ain’t broke…

Pictured are Snipers from 34 Squadron, The Royal Air Force Regiment based at RAF Leeming, undertaking Live Firing Tactical Training at the Otterburn Training Area. (MoD Crown Copyright)
