For many people, the opening of the arch, which has already become a landmark on the clifftop, is the result of a very long campaign. David Johns reports, talking to Parade Commander Alan Warren and veteran Raymond Whitewood.
Pictures just in from Folkestone, where Prince Harry is dedicating the new memorial arch in the town.
Prince Harry is leading Folkestone's First World War centenary commemorations. He will dedicate the Step Short Arch before meeting veterans in the harbour.
Prince Harry will unveil a memorial arch and lay a wreath when he visits an educational charity set up to remember the millions of men and women involved in the First World War.
The commemorative event, organised by Step Short, will take place in Folkestone, Kent, today, to mark the centenary of the First World War.
The prince will also take the salute of a military and civilian parade before walking down the Road of Remembrance to meet some of those who will have taken part in the parade, a Kensington Palace spokesman said.
Step Short is an educational charity which has worked to ensure that all those who passed through Folkestone during the First World War are remembered in an appropriate way during the centenary year.
The spokesman said: "Folkestone played an integral part in the Great War as the port of embarkation and return, to and from, the Western Front for millions of men and women."
The official unveiling of the memorial arch will be the centrepiece of a military and civilian parade along The Leas and down to the harbour, he said.
The military parade will be led by the Band of the Brigade of Gurkhas and include members of the three uniformed services.
This will be followed by a second group made up of 800 veterans and civilians led by Folkestone Pipes and Drums.
After pausing at the arch for the unveiling, both the parades will continue down the Road of Remembrance to Folkestone's harbour.
The spokesman said: "At the top of the Road of Remembrance, members of the parade will be given the 'Step Short' order, just as the servicemen were given during the First World War.
"The order was given to allow them to shorten their stride as they descended the steep slope of Folkestone's Road of Remembrance (then known as Slope Road) on their way to the harbour and a boat to the Western Front.
"Shortening their stride allowed those marching to negotiate the slope safely.
"For many it was their last time on British soil before heading to the battlefields of France and Belgium."
The Duke of Cambridge and Prince Harry enjoyed a charity polo match at Coworth Park near Ascot, in Berkshire, today.
They were playing in the Audi Polo Challenge, a two day event to raise tens of thousands of pounds for the Royal Marsden Hospital, Skillforce and Sentebale.