The BBC has revealed how it plans to mark the centenary of World War I.

Programming and events will span four years, across television, radio and online, from 2014-2018, echoing the time frame of the war itself.

"I want 2014 to be remembered for our national commemoration of all those who served on the battlefield and on the Home Front," said BBC chief Tony Hall.

"And a chance for us all to learn something new about a war we think we know well."

The season will include 130 newly commissioned programmes, spanning almost 2,500 hours....