Developer Scira Offshore Energy Limited commissioned a thorough site survey as part of its preconstruction preparations ahead of Dutch specialist Van Oord starting foundation work for the 90 turbines.

The bomb was found at the site of one of the foundation locations in the north-west of the site.

The survey took almost four months and covered around 44 square kilometres, including the wind farm site and cable corridor.

The work was carried out by Gardline Environmental Ltd who discovered 52 suspicious objects which were investigated by divers.

While most of the targets were debris or geological concentrations, several anchors and an old cannon were found, as well as the unexploded bomb.

The bomb was found by divers from diving specialists Red7Marine and verified and detonated with explosives by disposal experts MACC International.

The Sheringham Shoal Offshore Wind Farm is owned equally by Statoil and Statkraft through the joint venture company Scira Offshore Energy Limited.

Statoil is the operator for the project during the development phase. Scira will be the operator of the wind farm.

Three explosive experts were killed yesterday when they tried to defuse a 2,000lb WWII bomb found on a German construction site.

The bomb was unearthed by builders during construction of a new sports hall in Goettingen.