An online map showing the location of unexploded mines and bombs around the UK coastliine has been launched to assist the developers of offshore energy projects such as wind farms and cable laying text.

The interactive Mine Map, developed by Suffolk-based company Ordtek, displays data about areas known to have been mined during the two world wars and unexploded ordnance (UXO) from military armament training and munitions dumping as well as details of previous UXO finds.

Ordtek, which has offices in Eye and at the OrbisEnergy building in Lowestoft, is currently carrying out risk assessment work on the world’s biggest wind farm site off Hornsea, near Hull, and ongoing safety support at the Race Bank site off the north Norfolk coast.

Last year, the company found 41 unexploded items within the Race Bank site, ranging from small rockets to 1,000lb high-explosive bombs, of which 36 were still live and had to be blown up offshore.

The company has also helped identify and recover 70 items from the Solent ahead of channel dredging for new Royal Navy aircraft carriers. These ranged from modern-day projectiles to 18th century cannon balls.

Ordtek director Lee Gooderham said: “We have been working all over Europe and thought it was a good idea to share data about offshore unexploded ordnance to help developers.

“Geophysical seabed surveys, including looking for potential UXO, are a routine part of assessing sites ahead of construction work. The Mind Map is revolutionary in the industry and has taken us three years to develop.

“It’s not the complete database, although finer detail will be available at a later date,” he added.

“However, it is helping developers to understand UXO hazards while making their initial tender bids for wind farm sites and it’s allowing vessel operators to begin risk assessments.

“It helps them to see how much potential unexploded ordnance there is in an area, and work out how much it might cost to dispose of it.”

The map combines a range of data sources, including information from the UK National Archives, the Hydrographic Office and archives in Europe. Ordtek has also liaised with military sources.

The sea off East Anglia saw heavy military wartime activity and was a prime area for dumping unused munitions. Mr Gooderham said post-war dumping records were sketchy as navigation was less sophisticated and, instead of heading to a chartered disposal spot, a ship’s crew sometimes simply threw it overboard on a corridor stretching back to harbour.

While it was possible to map known mining and dumping areas it was not feasible to chart every unexploded torpedo and bomb whose positions were not recorded. However, they would be located during the more detailed surveys, as happened with the Race Bank finds, which were potentially the most explosive batch Ordtek had found so far.

Once UXO is confirmed – often using remotely operated vehicles (ROVs) and divers - the details are passed to military and civilian bomb disposal experts who carry out clearance ahead of onsite work starting.

Mr Gooderham said the process from desktop risk assessment to final clearance could take over three years on large projects.

He said the Mine Map, which covers the UK Exclusive Economic Zone, was already proving popular, and he planned to roll it out more widely across European waters.

Mr Gooderham, 38, has spent 16 years doing civilian explosive and UXO remediation work, including projects in the Middle East and Africa.