ROYAL Navy bomb disposal experts were today due to dispose of a Second World War mine found in Portland Harbour.

The one-ton German air dropped ground mine was discovered lying on the harbour seabed during a dredging operation.

A 1,000-metre exclusion zone was introduced and the Explosive Ordnance Disposal (EOD) team from Plymouth was alerted.

Experts had to wait until today – for improved weather conditions – to carry out a controlled explosion in Weymouth Bay.

The Maritime and Coastguard Agency said the mine was found during a routine shoreline survey on Tuesday.

It was lifted from the water but carefully replaced once it emerged exactly what the item was.

Portland Coastguard contacted the EOD team, who dispatched the Royal Navy’s Southern Diving Unit 1.

Lieutenant Commander Richard Talbot, the naval officer in charge of the unit, said it was a ‘significant item of ordnance’.

He said: “These things were put on an aircraft and dropped into the sea. They floated down on a parachute, which fell off when it hit the water.

“Lots of people ask how often you find these things. You can’t really answer that – it’s very random and we might not find anything else for six months now.”

Lt Cmdr Talbot said his team was hoping to dispose of the mine yesterday but poor weather made it impossible.

“The safety of the public is key,” he said. “With the conditions yesterday, it was never going to happen.

“You can do these things in marginal conditions but, while it’s old, it’s still ordnance and you have to treat it with a great deal of respect, as we all do.

“Luckily it was in around 15 metres of water. If you’ve got water over it, it does lessen the impact of any explosion.

“Also, the weather wasn’t exactly lending itself to people getting out on the water – Portland Harbour was very quiet yesterday.”

The exclusion zone remained in place throughout yesterday and coastguards warned shipping to steer clear.

Lt Cmdr Talbot’s team will carefully lift and tow the ordnance to a safe area for disposal.