THE threat of U-boats attacks in Morecambe Bay was a real one during the First World and much effort was put into preventing the underwater menace getting too close to key ports.

German U-boats made attacks near Whitehaven and off Walney using deck guns but it was feared they could also be used to lay mines.

Places like Whitehaven, Barrow and Heysham would have been patrolled by naval vessels and anti-submarine nets would be stretched between converted trawlers.

Today’s pictures were taken in Morecambe Bay by a Barrow photographer and are believed to show these heavy metal nets in operation.

They were spotted among a collection of postcards at collectables shop Pepperland Collect in Scott Street, Barrow.

They were made up of large circular links and could be moved to let friendly ships into harbour.

The Royal Navy was desperately short of mine sweepers, so it commandeered fishing vessels.

One of their dangerous tasks was to patrol ahead of warships seeking out mines.

In the early months of the war, the techniques of dealing with mines were still being learned – often with tragic results.

During the war, the Germans laid 43,000 mines and 200 British mine sweepers sank in dealing with them.

Close to 3,000 trawlers and drifters were taken over by the Royal Navy, or specially built, for mine and ant-submarine duties during the conflict.

The fishermen, supplemented by naval officers, had to cope with all weather conditions.

They dealt with mines, supplied bigger ships and were even sent into battle as “Q Ships” – acting as innocent-looking bait for U-boats but with hidden deck guns which could be put into action within seconds.

The crew members would be entitled to the Merchant Marine War Medal issued by the Board of Trade.

Recipients also qualified for the award of the British War Medal.