WATCH: Britain and World War I

"In Flanders Fields the poppies blow Between the crosses, row on row That mark our place; and in the sky The larks still bravely singing, fly Scarce heard amid the guns below. We are the dead. Short days ago, We lived, felt dawn, saw sunset glow, Loved and were loved, and now we lie In Flanders Fields. Take up or quarrel with the foe: To you from failing hands we throw The torch; be yours to hold it high. If ye break faith with us who die We shall not sleep, though poppies grow In Flanders fields." Flanders fields, a poem by John McCrae, describes a real place: the region of the Western fronts in the First World War, where more than half a million British soldiers and a hundred thousand more from the British Empire died between 1914 and 1918 - the majority of Britain's casualties in the conflict. They are commemorated in Britain today by the poppy, a flower that grows wild in Flanders. Hello, I'm Nick Dennis and I'm here in London, where I was born and raised, to explore the British experience in the First World War. Britain never meant to enter a would that will kill a generation of its young men. Unlike many of the other major powers, Britain wasn't part of a grand alliance and didn't really have a reason to fight - at first. Russia and the Austro-Hungarian Empire were ready to fight over Serbia. France and Germany were ready to resume their lingering hostilities over the territory of Alsace-Lorraine - but Britain didn't have a major reason to join the war at first, and was unprepared to fight it. In fact, even though the country had a large navy, it had one of the smallest armies in Europe. I'm here with Nick Hewitt, head of collections and research at the National Museum of the Royal Navy. DENNIS: Where are we? HEWITT: So we are inside HMS M33, which is our shallow water bombardment monitor which served in the First World War, so this ship was at Gallipoli, at the Dardanelles, in the First World War. DENNIS: Fantastic. And what was the size of the British Navy before 1914? Hewitt: So before 1914, the Royal Navy was the biggest and most powerful navy in the world. It was absolutely huge - at its core with dozens of dreadnought battleships, and then hundreds of cruisers destroyers - just the biggest fleet in the world. DENNIS: Okay and why do they have such a big fleet? Why did they need it? HEWITT: So Britain alone was a small coastal island. What made Britain powerful was her colossal trading empire, which spanned across the whole world, and in order to absorb the wealth from that Empire and keep the country strong, trade had to be protected, and the Empire had to be protected - and what you needed to protect that Empire was a strong navy. DENNIS: So why was the expansion of the German navy such a problem for the British? HEWITT: so the Germans felt that a navy was the way to make themselves a world power, and the Kaiser actually talked about that, but for the British it was an existential threat - any threat to those sea lines of communication meant a threat to Britain's very existence as a world power. DENNIS: So by Germany building up its own navy, did this help push Britain into war? HEWITT: Yeah absolutely, what you had was a ruinously expensive arms race, so every time the Germans built ships, the British had to respond. But the problem for the Germans was that, this was a race they could not win, because the Germans were also trying to build the most powerful army in Europe - the British weren't. The British could focus all their wealth and resources on their fleet. So every time the Germans built a new class of battleships, the British responded and what happened was, more ships got built but they got bigger and bigger and bigger - the guns on them got bigger and bigger and bigger - and this was absolutely key to Britain joining the war. DENNIS: Britain had a huge navy, but it had by far the smallest army of any major European power in 1914 - about 250,000 men scattered across its vast empire. But this army included some of the most experienced units in the world, in particular, the guards regiments - elite soldiers for whom war was a profession. I'm here at the Guards Museum in London to meet with Andrew Wallace, director of the museum. DENNIS: um, so who are the guards regiments? WALLACE: The guards regiments are the five regiments that have the honor, the duty, and the privilege of guarding the Sovereign and the Royal Palaces, and it's a privilege they've held since 1660. DENNIS: So, who were the members of the guards regiments in 1914? WALLACE: The regiments would have been made up of a complete cross-section in British society. The Officer Corps would have been drawn largely from the landed gentry. There is still a very strong family link within the officer corps of guard regiments, and if you go outside to see the change of the guards ceremony, you will probably find that the officers on parade are probably wearing their grandfather's bearskin and carrying their grandfather's sword. So it's very much a generational, handed-down father-to-son type of a role. The non-commissioned officers would have been the middle classes, and the guardsmen would have been from the working classes - so a real cross-section in British society. DENNIS: And what was Britain like in 1914? WALLACE: Britain was still very much the powerhouse of the world - the Industrial Revolution, the introduction of steam into the industrial processes - we were still very much the pinnacle of the commercial world, if you like. The Empire basically covered a quarter of the face of the globe, and we were bringing goods in from all over the world, processing them here in the UK, and selling it to the world. So it was a time of great prosperity for the upper and middle classes. Not so much for the working classes, who were still very much downtrodden, both in their minds and in reality - so it was starting to be a bit of a hotbed of insurrection, with the working classes actually deciding, this isn't right, this cannot be right, and you had the beginnings of the Labor Party being formed. So in terms of business, we were flying, but in terms of internal strife, it was starting to be a bit of a pressure cooker. DENNIS: In early 1914, the British government wasn't interested in getting into war on the side of the Entente. Rather, British policy in Europe was mainly aimed at making sure that no one European state was able to dominate the continent. Specifically, the British government wanted to keep the major European powers away from the ports of Belgium. The Belgian seacoast, and in particular the region known as Flanders, was the potential invasion route to the British Isles. For this reason, Britain had guaranteed Belgian neutrality since 1839. WALLACE: Belgium and London are tied together through the Treaty of London, 1839. So, the Kaiser was convinced that Britain wouldn't mobilize, and when Britain did mobilize in support of their Belgian allies, he said, "You've gone to war over a scrap of paper". But, by the fourth of August, Britain had declared war on Germany. By early September, we have boots on the ground in France, and the rest, as they say, is history. The Germans came forward, Britain and the allies drew up their lines, and in a line from the channel down to Switzerland, they faced off against each other - dug in - and then you had many, many years of bombardment and senseless killing. DENNIS: So, you just mentioned the trenches. What was trench warfare like? WALLACE: I think the only word that can sum it up is grim. The trenches were, in some cases, quite well formed. In other cases, it was literally just a scrape in the ground. Anything which got to you below ground level was better than being out in the open. The only problem with a trench is, as soon as you've dug it, if it rains, it fills up with water - that water then mixes with the soil, that becomes mud, and for years on end, both British and German soldiers were standing often waist-high in mud. The first thing to hit you was "trench foot" - your feet would literally rot inside your boots. The rats would eat anything, including you, if you were not fast enough to dispatch them. Supplying the trenches - massively difficult, so the privations of no food, no fresh water, not being able to clean yourself, the lice in the uniforms - it was horrendous. And this went on for years on end. DENNIS: With casualties mounting, Britain quickly found that its small professional army wasn't enough, and they began to rapidly expand that army. They knew that more men would enlist if they thought they could serve alongside their friends. The result, was "pals" battalions - entire businesses, streets, and towns who signed up to serve together. Unfortunately, this meant that, when things went badly, entire communities suffered devastating losses. For example, the "Accrington pals", 700 men from neighboring towns in Lancashire, suffered 235 men killed and 350 men wounded in about 20 minutes during the Somme offensives, during 1916. The war was devastating to the British nation. About 700,000 British servicemen died between 1914 and 1918. This represents about 8% of those who had force in the war, or one in every 12 men who enlisted. This isn't even counting the hundreds of thousands who served Britain from around the empire - Africa, Asia, the Caribbean, Canada, Australia, and New Zealand. Many of the dead were left buried in Flanders Fields, their graves covered in poppies - one of the few plants able to grow in soil ruined by war. It is for this reason that Andrew Wallace and the Guards Museum built this Flanders Fields Memorial Garden, here in London, to remember those who served. It was built in 2014, to mark the centenary of the outbreak of the war. "Iron are our our lives, molten right through our youth. A burnt space, through ripe fields, a fair mouth's broken tooth." Isaac Rosenberg, who grew up in the East End of London and was in a a Bantam Batallion - soldiers who were smaller than 5 foot 3 - wrote these lines as he reflected all the changes that war brought: hardness, the passion of youth, loss, and the destruction of beauty. Rosenberg, of Lithuanian-Jewish heritage, is an example of the diversity of British troops serving in the war, and the destruction it caused. He was killed only a few months before the war ended. The great war remains an important feature of the culture of Britain, and every November the 11th, people all over the country wear poppies, as a reminder of the loss of life between 1914 and 1918, and subsequent wars. The phrase "never again" was used after the war, in the hope that no more young men would die in fields far away from their homes. Just over 20 years later, the phrase seemed meaningless - the Second World War had begun.