The British army suffered its bloodiest day on the first day of the Battle of the Somme exactly 100 years ago.

More than 1,000,000 servicemen were killed or injured on all sides as the British and French armies fought the Germans between 1 July and 18 November 1916.

Commemorations have been taking place in Britain and in France to mark the 100th anniversary of a battle which for generations, has symbolised the senseless slaughter of the Great War.

Robert Hall reports.