Somme centenary: Queen leads vigil at Grave of the Unknown Warrior
30 June 2016 Last updated at 23:27 BST
The Queen is leading events to mark 100 years since the Battle of the Somme.
She was joined by the Duke of Edinburgh at a service at Westminster Abbey, where she laid a wreath of flowers on the Grave of the Unknown Warrior.
Services have also been held in Scotland, Wales and Northern Ireland on the eve of the centenary of the World War One battle.
Nicholas Witchell reports.