While much has been written on how British military kit has changed over the years, the importance of proper nutrition to the effectiveness of a fighting force cannot be ignored.
As either Napoleon or Frederick the Great once said - depending on who you ask - an army marches on its stomach.
But how far have things come for British troops in the last century?
The Napoleonic Wars (1803–1815)
During the Napoleonic Wars simple, nonperishable food (such as that shown above) was initially provided to troops.
They were fed a pound of beef a day, and a pound-and-a-half of bread, while morale was kept high through a daily ration of a pint of wine or a third of a pint of gin or rum.
During the conflicts, however, the partnership of Donkin, Hall and Gamble set up a London canning factory, which was the first to use tinned iron.
By 1813 they were selling preserved food to outbound ships on the south coast, and the British Admiralty were soon placing large orders for meat preserved in tin cans.
The inventions had a major impact on how food could be delivered to troops engaged in conflict, with supplies able to be preserved and protected from damage before consumption.
Tinned emergency rations consisted of a meat 'dinner' in one end and cocoa in the other. By the time of the Boer War they were designed to sustain a soldier for 36 hours while on active service.
The Boer War (1899-1902)
Hardtack biscuits like these were a staple of soldier's diets during this period - and the butt of many jokes.
This example was given to a member of the Royal Army Medical Corps around 1914 whilst en-route to Thessaloniki, Greece on a troopship.
These type of biscuits were known as 'Liverpool pantiles' (a type of roof tile) due to their texture and shape.
World War One
During the First World War tinned rations by 'Maconochie' had become a very familiar component of British soldiers' daily life and diet.
They were more blamed than praised, however, with many considering them only edible if mixed with something else. Some others did like it, though.
John Brophy and Eric Partridge, authors of Songs and Slang of the British Soldier, described it as: "A tinned ration consisting of sliced vegetables, chiefly turnips and carrots, and a deal of thin soup or gravy." They added:
"Warmed in the tin, 'Maconochie' was edible; cold, it was a man-killer. By some soldiers it was regarded as a welcome change from bully-beef."
Imperial War Museum historian Laura Clouting says: "Army food was basic but filling.
"Soldiers could expect to receive around 4,000 calories a day to fuel their arduous work. Tinned rations, like 'Maconochie' stew, formed the bulk of a man's diet."
"Troops were supposed to receive one hot meal a day. But soldiers sometimes went hungry because ration parties were unable to reach them in trenches under shellfire.
"Parcels from home, eating meals behind the lines and 'scrounged' treats helped to liven up the diet. Wealthier men requested hampers from home, one noting that 'after seven days bully beef, we felt we must have lobsters and white wine'."
World War Two
By the time of the Second World War much of soldiers' ration packs contained canned food.
They could expect to find items like tins of meat, packs of biscuits and packs of mints given to them.
Also commonly provided were boxes of matches and - of course- tin openers, some of which could double up as spoons.
Morale, meanwhile, was kept high through the provision of chocolate (the example below doesn't look particularly appetising as it was handed to a Dutch civilian by a British soldier during the liberation of the Netherlands and preserved as a precious gift)...
By the time of the War in Afghanistan, troops on active operations were being given rations designed to meet all their nutritional requirements.
The items in their packs aimed to provide a constant release of energy, with a minimum of 4,000 calories and high levels of carbohydrates.
Meals for breakfast, lunch and dinner were all included, along with biscuit and sweet snacks, hot drinks and energy drinks, disinfectant wipes, water purification tablets and dental chewing gum.