NEW Forest archaeologists are to survey hidden remains of a Second World War site where Britain’s biggest bomb was first tested.

They will be using innovative techniques to discover the remains of a target range near Fritham where the bomb,|which weighed 22,000 lbs, was dropped.

The earthquake bomb Grand Slam was designed by bouncing bomb inventor Barnes Wallis to penetrate the ground and send shockwaves to damage enemy bunkers.

The tests at the Ashley Walk bombing range included a unique target building, titled the|“Ministry of Home Security Target”, but nicknamed the “Sub Pen” by locals because of its likeness to German submarine pens.

But after the war it was buried, hidden from view underneath the landscape for more than 60 years.

Now archaeologists, led by the New Forest National Park Authority, will use ground-penetrating radar and electrical imaging to discover what remains of the “Sub Pen”, confirm whether chambers inside still exist and whether the structure needs future conservation.

The non-intrusive techniques could also shed light on local rumours of buried bombs or airplane parts inside the structure. The work is part of The New Forest Remembers World War II Project, funded by the Heritage Lottery Fund and supported by a wide range of organisations, including ExxonMobil and English Heritage.