Tom Bayly
BBC News, at Westminster Abbey

A wide range of organisations are represented at tonight's service. A large queue outside the Abbey now made up of smartly-dressed representatives of bodies including the armed forces, emergency services, Salvation Army, Scouts, Girl Guides and many charities.

Keith Rogers emails: : My grandfather joined the war in 1915, he became an ambulance driver and mechanic. He was at Verdun I am told, in the 14th 18th volunteer Ambulance brigade, and drove up to the front line during the night collected the wounded then back all before daylight again.

The service at St Symphorien cemetery is brought to a close by the Anglo German choir as darkness falls.

Clive James in Maidstone, Kent emails: My Great Uncle George Potts was in The 4th Battalion The Worcestershires, which formed part of the invasion force sent to Gallipoli. He was killed on the 28th of June 1915 aged 25. In a sense he was probably one of the first US citizens to serve in the Great War. He like so many other young men of that time, were served by a leadership deploying strategies of the 19th century, against newly developed 20th century weapons. This led inevitably to such catastrophic losses. Soldiers of course risk their lives but, we must never forget their suffering and sacrifice.

Loose flowers are laid at the ceremony, rather than wreaths or poppies, which became a tradition after the end of World War One.

Lanterns are placed by those attending the St Symphorien commemoration, in recognition of the words of a German chaplain who said "let there be light" at the cemetery's dedication ceremony in 1917.

Archbishop of Canterbury Justin Welby gives a blessing and a piper plays as the sun sets at St Symphorien cemetery.

The Last Post is played by Sgt Gavin Hall after David Cameron, Prince William, the King of the Belgians, and the Irish and German presidents laid flowers.

News from 1914
The world on the brink of war

"Was it for this the clay grew tall? O what made fatuous sunbeams toil. To break earth's sleep at all?" Futility by Wilfred Owen

Image source, Getty Images

Poetry in World War One

Wilfred Owen is considered one of the greatest soldier poets. His poetry described the horror and futility of war. Tragically he did not survive the conflict. He died on 4 November 1918.

Here's the scene at St Anne's Cathedral, Belfast, where First Minister Peter Robinson and Northern Ireland Secretary Theresa Villiers were among those attending a commemoration service. Picture by the BBC's Naomi McCafferty

News from 1914
The world on the brink of war

Image source, John Duncan

Miners in World War One

Men who had worked as miners were engaged in secret but essential work beneath the Western Front. They built explosive-packed tunnels along the trenches, often searching out and destroying German tunnellers busy digging the other way. This deadly war of nerves was waged mainly by miners with little or no military training.

Writing at the end of 1916, Field Marshal Haig noted that 'The Tunnelling Companies still maintain their superiority over the enemy underground, thus safeguarding their comrades in the trenches."

Tom Bayly
BBC News, at Westminster Abbey

The first members of tonight's congregation have started to arrive at Westminster Abbey. Some 1,700 people are expected for the service, which begins at 22:00.

News from 1914
The world on the brink of war

The President of Germany and King of Belgium shook hands as they unveiled a commemorative plaque at the university at Leuven (Louvain in French).

The town and university itself were the site of great violence 100 years ago, when invading German soldiers ransacked it in August 1914, killing many civilians and burning the university's famous library, along with many other important buildings.

The burning of Leuven was one of a number of atrocities committed in the early weeks of the war that transformed many people's understanding of what was now at stake. Find out what happened when thousands of Belgian refugees fled to Britain in 1914.

Prince Harry reads a letter written by Private Michael Lennon to his brother in 1915, after he arrived at the battlefields of Gallipoli.

"Well Frank, I suppose we are for it tomorrow, if we don't get shelled on the way… I can only hope that we have all the luck to come through the night and if I should get bowled out - well it can't be helped. I shall pack up to the place 'Where falls not rain, nor hail, nor any snow, and where the wind never blows loudly', but as I have said before, I am looking for something better than that and I shall see you again when the job is done."

As the Mons commemorations continue the London Symphony and Berlin Philharmonic orchestras collaborate in a performance of George Butterworth's 'Shropshire Lad' Rhapsody, which, Dan Snow says, "evokes an innocence lost". Butterworth was killed in the Battle of the Somme in 1916.

Image source, PA

Here's a picture of the Queen attending the service at Crathie Kirk, near Balmoral. Her uncle, Captain Fergus Bowes-Lyon, was killed at the battle of Loos in 1915

An Anglo German choir at St Symphorien performs wartime songs including Muss i' denn zum Staedtele hinaus, It's a long way to Tipperary and Pack up your Troubles.

Robert Hall
BBC News

The sun is setting above the trees of St Symphorien.

National leaders, military chiefs, and the families of the fallen are reflecting on the dark days of war.

British Prime Minister David Cameron has spoken of the silent victims of war and pledged that we will never forget.

A few yards away the gravestones of the first and the last British soldiers to die during four years of war shine white in the TV lights.

British and German drummers perform side by side at the Mons ceremony.

World War One was not "the war to end all wars", Mr Cameron says. It was "the precursor to another desperate and violent conflict, just two decades later".