The Prime Minister said an advisory board of former defence secretaries, chiefs of staff and military specialists would bring together ideas for nationwide commemorations of the Great War.
He told an audience at the Imperial War Museum that his ambition was to have a "commemoration that captures our national spirit in every corner of the country".
"A commemoration that, like the Diamond Jubilee celebrations this year, says something about who are as a people," he continued.
More top news
Some of the world's biggest football clubs will ask FIFA to move the 2022 World Cup to spring.
This photo of African migrants attempting to cross the border into Europe while golfers tee off has gone viral.
Staff at GCHQ have come together to help launch this year's Poppy Appeal by forming a giant flower in the centre of the famous building.