Device found on Norwich’s Northern Distributor Road likely to have been planted in preparation for German invasion

Chemical mine found in Horsham St Faith. Picture: 6 Alpha Associates

Chemical mine found in Horsham St Faith. Picture: 6 Alpha Associates - Credit: Alpha 6

A device found on land being developed for the Northern Distributor Road was likely to have been planted by British forces in preparation for a German invasion.

The scene of the crash in Rackheath

The scene of the crash in Rackheath - Credit: Archant

The Mk 1 chemical mine was spotted by contractors on Tuesday morning during a search for unexploded devices around the former RAF Horsham St Faith airfield.

Experts believe the object was buried during the Second World War as an 'area denial' device and could have once contained a quantity of mustard gas or phosphorous.

Its discovery on land off Bullock Hill resulted in a 200m police cordon around the site as bomb disposal experts from the Royal Logistics Corps examined the object.

Ten people were also checked over by paramedics at the scene to ensure they had not been affected by the contents of the device.

A spokesman for Norfolk County Council said: 'The item found was an empty Mk 1 chemical mine, initially produced in 1914, but adapted for defensive purposes which is probably why it was in that location.

'It may have contained incendiary or illumination fill, but when found it had already been damaged, probably, by ploughing, and any contents had long since dissipated.

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'However, it potentially still contained an explosive expulsion charge, hence the requirement for bomb disposal.'

The mine was found by specialist contractors 6 Alpha Associates, which has been employed by the council to check for unexploded ordnance near the NDR.

Similar checks have already been carried out near RAF Rackheath, where the remains of a crashed P-51D Mustang were discovered.

A council spokesman said the mine's discovery would not impact on the delivery of the 12.5-mile route, which runs from the Postwick junction of the A47 to the A1067 at Taverham.

Robin Rickard, programme manager from 6 Alpha Associates, said the mine was one of many types of anti-invasion devices installed along coastal airfields during the war.

He said: 'It would have been initiated by a trip wire, which would have basically thrown mustard (gas) upwards and outwards, so anyone in the vicinity would have got a lungful.

'Chemical weapons pose a very different hazard to conventional unexploded ordnance, and detonation must be avoided in order to

prevent the discharge of harmful contents.'

Mr Rickard said other anti-invasion devices included burying pipes filled with nitroglycerin underneath airfields, which could then be detonated to render them useless.

But he stressed there was no indication that such methods had been used at RAF Horsham St Faith.

After the mine was discovered using metal detectors, it was removed by a bomb disposal team based in Colchester.

An army spokesman said the device was packaged, sealed and removed for 'safe disposal'.

Have you made an interesting wartime discovery? Call Luke Powell on 01603 772684.