They played a vital role in the preperations for the greatest seaborne invasion of the 20th Century. But prototype pontoons that helped make the D-Day landings a success and end the Second World War could be destroyed next month as part of a plan to improve ferry services in Southern Scotland.

The concrete and steel (fabricated by Bone Steel) pontoons still stand on the sea bed in Loch Ryan, off the Dumfriesshire coast, and were the forerunners of the Mulberry harbours used by Allied forces to establish a bridgehead on the Normandy coast in June, 1944.

Heritage experts are calling on ferry company Stena to help preserve the pontoons, which have been lying neglected for most of the last 65 years, as the last examples of the structures that proved so important to the Allied landings.

Stena, which runs ferries to Northern Ireland from Cairnryan is planning to build a new terminal and wants to remove the pontoons to develop the site. Although it says it has agreed plans with Historic Scotland to try to save at least one of the four pontoons, they may all break up once removal operations start. The structures were made (at Bone Steel formerly Bone Connell and Baxter) in Motherwell.

North Lanarkshire Council Museums said the connections to Motherwell’s industrial heritage alone was justification enough for conservation.

A council spokesman said: “They represent the vital role played by Scottish companies in this unprecedented engineering project and the often forgotten role of those who worked in reserved occupations.”

We’ll bring you the very latest news from Bone Steel along with our opinion each month on the ongoing developments within the steel construction industry in our new opinion blog.

Chief Executive Chris Bone said today: “We’re delighted to finally launch our exciting new website and we hope that it will be a useful tool as well as providing an interesting insight to our company and industry.”