So called 'practice trenches' at Browndown in Gosport, Hampshire that lay beneath heathland for decades have been granted heritage protection.
The site was used for training troops in the Great War and was rediscovered from aerial photos in 2011.
Following input from Historic England, the Department for Culture, Media and Sport (DCMS), has agreed that this should be designated as a scheduled monument.
The two sets of trench systems, separated by no-man's-land were found when a council worker discovered a photograph of the area dating from 1951. The trenches subsequently became overgrown with bracken and gorse.
Above and below: The site (images from BBC / Historic England)
The system of trenches is not the only one in the UK: the Redmires Trenches near Sheffield are also designated as a scheduled monument.
Historic England stated that it was likely that the Royal Marines Light Infantry and the Hampshire Regiment trained at Browndown before leaving for the war via the nearby port of Southampton.
The site is open to the public, with the trenches situated on Ministry of Defence land south of Alver Valley Country Park.
Above: Image from BBC / Historic England)