Among the most elegant, and most prophetic, words spoken about war were those of Sir Edward Grey, the Foreign Secretary, on the evening of 3rd August 1914. Britain was not yet at war, but the belief was that British participation in the already ongoing European war could not now be avoided.
Grey's words have become so closely associated with the outbreak of war that they have been taken as the theme for this week's commemoration.
In a generation of politicians that included David Lloyd George and Winston Churchill, Grey was not the most charismatic nor the best orator nor the greatest man of letters. But it was his speech to the House of Commons on 3rd August that defined the British position and caused the majority, in Parliament and in the country, to accept that Britain had just cause to go to war. It was 'a statement destined to remain memorable in the history of the world', said the Times.
According to his own memoirs, it was after making that speech that Grey, while looking out of the window of his rooms in the Foreign Office, spoke the words to a friend who was with him.
'We shall not see them lit again in our lifetime.'
The Great War changed Europe and the lives of many families not just for Grey's lifetime (he died in 1933) but forever.
Four Empires fell - the German, the Austrian, the Russian and the Turkish. The consequences are still being felt in parts of Europe and in the Middle East today.
The Peace of Versailles, which was recognised as flawed almost before the ink was dry, contributed to the great financial problems of Europe in the 1920s and to the Second World War, which in turn led to the Cold War.
Grey's own party, the Liberals, yielded to a Coalition government in 1915. The party was deeply split and never again held office.
The Great War had a much greater impact on the people of Britain than any previous war. Every family must have been touched by it in some way.
For Britain, this was the first war fought with a conscript army (from 1916). 5.7 million British men served in the Army at some time during the war. A further three million Imperial and Commonwealth troops served. Men also served in the Royal and merchant navies and the Royal Flying Corps and Royal Air Force. About one million died. Many more were left disabled, with lasting impact on their families.
Millions more men and women worked in munitions and other industries related to war. Many moved away from their homes to do so, sometimes taking their families with them, changing the course of their lives and those of their descendants.
This war was fought on the Home Front, something which the Britain, as an island, was not accustomed to. Aerial warfare brought civilian casualties. The U Boat campaign brought the country near to starvation.
This week we should remember not just the men who went to fight and who died, but also those who came home disabled, and the women and children whose lives were changed by the war.