Human skull, five large bombs and cannons dredged from Portsmouth Harbour

A total of 3.2m cubic metres of sediment, the equivalent of 12,800 Olympic swimming pools, were removed during the dredging operation carried out to deepen the harbour mouth.

It comes as the 65,000-tonne HMS Queen Elizabeth is due to reach its home port of Portsmouth Naval Base in the next few weeks.

Defence Minister Harriett Baldwin said: ‘Upgrading the future home of HMS Queen Elizabeth is another completed step in the carrier’s journey to becoming the nation’s flagship, ready to operate around the world and help keep us safe.

‘The work to prepare for our naval future has unearthed objects from our naval past which are part of Portsmouth’s proud maritime history.’

The Defence Infrastructure Organisation (DIO) awarded a contract to Boskalis Westminster to carry out the dredging work which uncovered eight cannons, an aircraft engine, 36 anchors and a human skull - which was passed to Hampshire police.

Also dredged up were a British torpedo, a German sea mine and five large bombs which caused major disruption to the area while each was made safe by the Royal Navy’s Explosive Ordnance Disposal team.

Captain Iain Greenlees, head of infrastructure at Portsmouth Naval Base, said: ‘The dredging was the culmination of 12 years’ work monitoring the seabed environment around the harbour and unearthed a huge array of items, some of which may be historically significant, and underlines again Portsmouth’s long maritime history.

‘Completion of the dredge is the final critical step in a wide range of activities preparing for HMS Queen Elizabeth’s arrival.’