The famous 'Mulberry harbours' were temporary portable harbours developed by the British during World War II to facilitate the rapid offloading of cargo onto beaches during the Allied invasion of Normandy in June 1944. After the Allies successfully held beachheads following D-Day, two prefabricated harbours were taken in sections across the English Channel from Britain with the invading army and assembled off Omaha and Gold Beach. They are now praised as one of the greatest engineering feats of the entire second world war. 

One of the industrial companies involved in the production of the harbours were Carr Bros Ltd, and Talbot Bros Ltd of Rotherhithe, London. A strategically placed residential area of the capital used as an industrial harbour, it was linked to the canals across the country via the thames. During WW2 Rotherhithe was an overwhelmingly maritime district and its main industry was ship making, repairing and breaking. Their factories closed not long after the war, but throughout the UK evidence of their waterborne defences can still be found. The majority of which are most likely at the bottom of our river beds, but some have become quite literally part of the landscape in the 70 years since their function was ever conceived. 

At the opposite end of the country, the Manchester Ship canal, built during the 19th century, was and still is the most direct and reliable method of reaching the city of Manchester from the mouth of the Irish Sea at Liverpool. The brilliant ingenuity of the British navy engineers during the production of Mulberry Harbour lead to the same idea being applied on a smaller and defensive scale around Britain's many estuaries, rivers and canals in apprehension of a possible German invasion in the event of a defeat in Europe. 

The homeguard worked tirelessly during the peak times of the war to ensure that precautions were in place to defend mainland Britain if the Germans pushed back the allied troops during the liberation of France into occupied Europe. Industrial production was running at full capacity and Manchester was one of the main districts in the north of England that held indispensable defences against the Germans, and with Liverpool in battered ruin from the blitz, the factories and emplacements in Manchester would be the first to be targeted in the event of an invasion on the western coast of the country. 

With the Manchester Ship Canal the only direct way to reach the city by water, four concrete barges were transported from London to a key point on the canal half way between the two cities in Warrington, at a point where the water flows inland for a quarter of a mile hidden behind farmland making them hard to spot from the air. If D-Day failed and the Nazi invasion were to take place, the homeguard planned to move the barges directly into the ship canal and intentionally fill their cargo holds with water. Effectively turning them into concrete boulders, this would prevent any ships from reaching their destination.

Despite their precautions, a home defence operation was never required and D-Day led to the liberation of Central Europe. The barges were forgotten and eventually eroded causing them to fill with water and sink into the shallows at the side of the canal. Whilst the overgrowth has consumed them for over 7 decades they are still incredibly well preserved and would take an ambitious operation to move, so they remain part of the surrounding farmland. The town of Warrington and neighbouring district of Trafford now have very few remnants left from the war effort after having seen extensive regeneration into the 21st century, but the barges still serve as a brilliant hidden reminder of how close we once came to war on our doorstep, and they will likely be here for many years still to come.