The Prime Minister has reflected on his own family's links to the First World War as he visited a cemetery where his great-great-uncle is commemorated.
Captain Francis Mount is remembered with an inscription on the wall of the Dud Corner Cemetery and Loos Memorial in northern France.
Captain Mount, a relative on David Cameron's mother's side of the family, was killed in action at the Battle of Loos as he fought as a member of the Royal Berkshire Regiment on October 12, 1915.
His name was among 1,800 servicemen remembered at the cemetery, 1,100 of whom are unidentified, in a rural site outside Lille.
The Prime Minister said visiting the site helps to "bring home to you the scale of the tragedy".
Speaking of his relative, Cameron said, "You see panel after panel, almost half the people he served with didn't come home.
"It does help to make a personal connection with this massive sacrifice that took place and I think it is a good way to try and understand what happened and the reasons why."
Richard Nichol of the Commonwealth War Graves Commission showed the Prime Minister around the cemetery.