Historians are to mark the centenary of the start of the Third Battle of Ypres by unveiling a new Hertfordshire Regiment memorial in Belgium this morning.

July 31 marks a century since the first day of the battle, which is commonly known in the public mind as Passchendaele.

At 11am this morning the Herts at War community history project will unveil a monument to the Hertfordshire Regiment at the battlefield – the unit’s first memorial outside the UK.

The Hertfordshire Regiment’s 620 men and officers were virtually wiped out in the first two hours of fighting on July 31, 1917 – attacking near the village of St Julien on what Herts at War member Dan Hill has called the most important day in the county’s military history.

All the regiment’s officers and 75 per cent of the other ranks were either killed, wounded or captured.

The service of dedication will be followed by a set of poignant guided walks across the battlefield.

North East Herts MP Sir Oliver Heald, who travelled to Belgium yesterday, will be among those attending the memorial dedication.

The Third Battle of Ypres lasted until November 1917. Historians differ on the exact number of casualties, with estimates generally between 400,000 and 500,000.

To find out more see hertsatwar.co.uk.