Thiepval Memorial, Picardie, France

The largest British war memorial in the world, the Missing of the Somme monument stands 47m high and contains the names of the 73,357 British and South African men who have no known grave and who fell on the Somme between July 1916 and 20 March 1918.

Over time, the majority of its 21 roofs had cracked and moved, allowing water to leak into the rooms in the structure and threaten its integrity. This had been exacerbated by the fact that the upstands had not been covered during the original build.

To rectify this problem, the Commonwealth War Graves Commission (CWGC), responsible for the maintenance of all British war memorials worldwide, called on specialist British contractor Bell Asphalt to perform the renovation.

"It's a modern solution that is extremely durable, allowing for thermal movement while retaining its shape," says Keith Collins, managing director of Bell Asphalt.

A Permanite-approved contractor, Bell Asphalt recommended Permaphalt polymer-modified mastic asphalt for the project.

"We are confident that this solution will provide protection for many years to come," says Keith Collins. "It is supported by a 20-year guarantee, but it should outlast that many times over."