The eve of the 100th anniversary of the Battle of the Somme is being marked with a candlelit vigil at Edinburgh Castle.

The bloodiest battle in British military history is being remembered at the Scottish National War Memorial, where members of the public have been invited to pay their respects to the fallen ahead of a service shortly after 9pm.

Reverend Neil Gardner of Canongate Kirk is conducting the service which saw veterans and cadets place candles within the shrine and a piper perform.

Edinburgh Castle is being floodlit red from dusk onwards as part of commemorations taking place across the UK.

Beginning on July 1, 1916, the Battle of the Somme was intended to achieve a decisive victory for the British and French against Germany's forces in the First World War.

By the end of the battle on November 18, British and Commonwealth troops had suffered 420,000 casualties, with 19,240 dying on the first day alone. French losses numbered around 205,000 and the German army suffered 465,000 casualties.

After 18 weeks of fighting, British and French forces had advanced less than ten miles into German-held territory.

Fifty-one Scottish battalions took part in the campaign, including the 16th Battalion Royal Scots which was largely composed of professional and amateur sportsmen and their supporters.

At the end of the vigil the Memorial will close to the public and representatives of regimental associations and services will keep watch until 7.30am on Friday, when soldiers were led into battle a century ago.

A morning service will see those gathered respect a two-minute silence to remember those who fought.

At Westminster Abbey in London, the Queen and Duke of Edinburgh will join the congregation for a vigil, while the Duke and Duchess of Cambridge and Prince Harry will attend events at the Thiepval Memorial in France, where 70,000 British and Commonwealth soldiers with no known grave are commemorated.