For decades they have withstood the threat of enemy fire, the hard steel of the Cold War and the wild north Norfolk weather.

But as they have stood silently overlooking RAF Coltishall, two important reminders of the county's military past have slowly become lost under rambling undergrowth and thick tufts of grass.

Now however, the fascinating war-time role of the distinctive fighter pen and the circular Pickett Hamilton fort is being brought back to the fore after they were unearthed by history buffs.

Finding them has been hailed as a leap forward in helping to map Coltishall's world war two history, before the remnants of its 1940s past was swept aside by the Cold War.

Work to uncover both structures has been spearheaded by Norfolk County Council, which bought the base for £4m in January and has outlined several possibilities for the station, including returning some land to farming, building new homes and providing space for businesses.

It is hoped the pen – a 'parking space' for Hurricanes and Spitfires – and the sunken fort, which was manned by machine gunners who would 'pop up' when the enemy attacked, can now be restored to something like their former glory, and form part of a heritage trail for visitors. David Gurney, historic environment manager at the council, said: 'We have really had a huge leap forward in understanding the layout of the site during world war two.

'When the site becomes more accessible and we start to allow people on, we want to tell the story of the site in world war two and the Cold War and this new information will allow us to do that.'

Uncovering one of Coltishall's three Pickett Hamilton forts, along with some of the world war two runway lights, was particularly exciting, Mr Gurney said.

And although the concrete fort is currently stuck in the down position and flooded with water, he hopes there may be a chance it could be fully restored so it can rise once more from the ground.

'It's a very exciting and surprising discovery,' he added. 'We knew they were here but we didn't know where they were or whether they'd survived. They could well have been swept away during the Cold War modifications for the air field.

'What was amazing is that no one on the site knew it was here, it didn't show up on aerial photos.'

The unassuming-looking fighter pen also had a secretive design. Laid out in an 'E' shape it would provide a 'parking space' for two fighter planes, but in the middle it housed an air raid shelter.

Mr Gurney said its construction was also unusual. 'It's a fortified pen made, interestingly, out of bags of concrete. To build the walls they got lots of bags of concrete and stacked them up,' he added. 'I haven't seen this anywhere else.' Coltishall was home to ten pens, which were scattered across the base in tucked away spots so if the enemy attacked they would not be able to destroy the fighting fleet in one hit. And while the exploratory work at Coltishall continues, Mr Gurney is already setting his sights on bringing some of the station's most recognisable icons back home. He added: 'What I'd love to do is have a replica Spitfire or Hurricane sitting in one of those pens, that would be fantastic.'