Photographs capturing soldiers posing with the dogs that helped carry messages, detect enemy troops and simply provide comfort in the trenches  while they were fighting during World War One have been found. Libby Hall, of Hackney in east London, has spent four decades collecting dog photos and stumbled on the collection of wartime snaps at a market stall. The pictures show soldiers, dressed in full uniform, posing fondly with the animals as well as whole companies with the animals that were likely to have been trained to act as messengers, scouts and seekers to find and help the wounded on the battlefield. Scroll down for video . Photographs depicting soldiers in World War One posing with the dogs they kept as pets and messengers have been uncovered, including this one of a Staff Sergeant (Horse Farrier) of the Army Service Corps (ASC) with the Corps pet dogs, Hissy and Jack, in France in 1916 . Around 20,000 dogs are believed to have been involved in the World War One - a testament to Britain's affection for dogs. The series of intimate pictures betrays the high regard placed on the animals - which were vital as the war moved to the trenches, either in providing comfort to soldiers or helping with tactics to foil the enemy. Dogs were used for a variety of purposes during World War One and later became known as the 'unsung heroes' of the war. The animals were used a lot by German troops and increasingly by the British and French - with troops training intelligent agile dogs such as Doberman Pinschers to carry messages and even seek out the wounded. In fact they became so important that in the early months of 1917, to hone the animals’ skills, the War Office formed the War Dog School of Instruction in Hampshire. Some were used as sentinel dogs, kept on a short leash to accompany guards on the top of the trench. They were trained to give a warning signal if an unknown person entered a secure area, so subtle the enemy would not have realised they had been detected. Dogs performed a number of vital roles for soldiers, acting as scouts and seeking out the wounded. The animals were highly regarded by their owners, such as Officers, Warrant Officers, Staff Sergeants, of the Army Service Corps (ASC) who pose with their company dog in 1917 . Dogs were quicker, more agile and smaller making them efficient messengers during World War One, like this dog pictured in France in 1918 . Others were used to act as scouts. Able to detect enemy scent up to 1000 yards away, these dogs were trained to run ahead searching for alien scents and give subtle signals to troops, such as straightening their tails or raising their backs, when an enemy was approaching. Companies also trained dogs to find the wounded on the battlefield and even carry messages. The animals were seen as more efficient than human messengers, able to cover greater distances and any terrain. They also presented less of a target to enemies and were able to carry messages from the first line of fighting troops to commanding officers in the rear. British forces also developed a technique used by the Germans in the 1800s to use dogs to help the wounded. Animals were typically equipped with simple medical supplies so soldiers found by them could make an attempt to treat their own wounds. German officers used many dogs during the war, often as messengers and to seek out the wounded, and are seen posing behind the lines at Le Cateau, France during Christmas 1916 (left), while two German Other Ranks officers were pictured posing with four puppies (right) Dogs brought soldiers and civilians together during the war, with civilians posing proudly with the animals in August 1915 alongside four soldiers - most of whom were from the Wiltshire Regiment (left), while a Corporal of the Worcestershire Regiment is with his dog (right) in 1917 . As life in the trenches became bleaker, some dogs were simply used as pets or mascots. The animals were seen as a psychological comfort to soldiers which could temporarily take away the torment of life in the trenches. They were also useful at removing rats and other pests, making life slightly more comfortable. A number of stray dogs were given to the army by organisations such as Battersea Dogs Home, after their usefulness to troops was recognised. The tradition of the military using dogs has continued, with the US military currently having a force of around 2,500 animals - some of which have been used in Afghanistan and Iraq. Ms Hall, 73, has been collecting photos of dogs since 1966 and She stumbled across the collection of dog photos, featuring soldiers during World War One, at a local market. Dogs are seen as man's best friend and were treated with respect during the war, seated for tea with two German officers in 1917 . The 209th (Norfolk) Field Company, Royal Engineers, of the 34th Division, pose with their dog - a vital member of the team during the war . She found out the photographs were destined for the skip and decided to buy the entire set to save it. Her latest collection is now the largest of dog photos, taken during World War One, and is being exhibited in London. She said: 'My collecting began by chance. 'I was a press photographer and discovered that a local junk shop in Dalston doing house clearances was simply throwing away old photographs. A member of the Swedish Navy poses with his dog in around 1915 - an example of how dogs were often kept as pets as a form of comfort . Dogs had a variety of uses during the war, from being companions to messengers and collecting much needed funds like this Airedale . Dogs were often used as mascots during wartime, and Bruce - a Rough Collie - was used by Moseley Road fire station in Birmingham in 1914 . 'I persuaded them to let me have them, really just to save them from the dustbin. 'I have lived with dogs all my life and began to be intrigued by the photographs that had dogs in them.' Libby started collecting pictures of dogs in 1966 and chose a selection of them appearing in the 1914-18 war to display in the exhibition. The exhibition is being held at Bishopsgate Institute, in Spitalfields, as a show entitled Dogs of the First World War. Entry is free and it runs until June 26. In ancient times the Greeks and Romans regularly used dogs as sentries during times of war, and sometimes the animals were taken into battle. Attila the Hun used powerful Molosser dogs in his campaigns, while the Spanish Conquistadors were said to have used armoured dogs that had been trained to kill. The soldiers set the dogs on natives as they travelled the globe conquering territories. In the U.S. the American pit bull terrier was used in the Civil War both as a means of protection for soldiers and to send messages. The dogs also appeared on propaganda and recruiting posters in the U.S. during World War I. In recent years in the U.S., some troops in Afghanistan and Iraq have been accompanied by military working dogs. The animals are paired with a handler after being trained for detection work, such as helping to search for survivors after an explosion.
Previously unseen photographs of soldiers posing with their dogs during World War One have been uncovered . The pictures portray the important role of the animals during the war, as scouts, messengers and even pets . Dogs provided a great comfort to men fighting in the trenches and could also seek out enemies and the wounded . Around 20,000 dogs are believed to have been used by troops on and off the battlefield during World War One . Libby Hall found the collection of intimate pictures and is now exhibiting the WW1 collection at a London gallery .