The 500 pound World War Two device was picked up during dredging work.
HMS Edinburgh In Portsmouth For Final Time
The last of the Royal Navy's Type 42 destroyers has sailed into port for the final time ahead of being decommissioned and scrapped.
HMS Edinburgh, which has clocked up almost 800,000 miles in its 30-year career, returned to Portsmouth Naval Base, following a farewell tour to London, where it took part in events to mark the 70th anniversary of the Battle of the Atlantic, and to its namesake city in Scotland, as well as Liverpool where it was built.
The ageing warship, which was flying a decommissioning pennant, was accompanied into Portsmouth Harbour by one of the replacement Type 45 destroyers, HMS Defender.
Families lined the quayside to welcome their loved ones home while a flypast was carried out by a Sea Fury of the RN Historic Flight plus a modern-day Lynx helicopter.
Edinburgh's commanding officer, Commander Nick Borbone, said:
``After the success of her final operational deployment in March, this has been a fitting finale to an illustrious career for HMS Edinburgh.
``The welcome, hospitality and warmth that we have received during visits to the capital, her namesake city and finally to her birthplace in Liverpool is clear evidence of a nation that holds the Royal Navy in extremely high regard.''
He added: ``Coinciding with the Battle of the Atlantic 70th anniversary commemorations, we have been able to open the ship to thousands of visitors across the nation all of whom have had a chance to experience a Type 42 for the final time and also see for themselves how the Royal Navy continues to play a vital role in protecting the interests of the UK.
``Sadly, Edinburgh and the Type 42 destroyers' part in that has come to an end but the new generation of modern and capable Type 45 destroyers are ready to take on the mantle from here.''
First Sea Lord Admiral Sir George Zambellas said: ``The Type 42 destroyers and their crews have served our country with distinction.
``Whether tackling narcotic smuggling in the Caribbean, defending the Falkland Islands or protecting civilians in Libya, not to mention saving lives through search-and-rescue operations, the ships have given outstanding service to the UK.''
Joy Allen, originally from Hartlepool but living in Portsmouth, was with her daughter, Eve, four, to meet Petty Officer Damion Allen as he arrived home.
She said: ``It's very nice to see him, I've missed him. It's a bit emotional with it also being the last time for the Type 42s.''
PO Allen, who served on Edinburgh for three years, said: ``It's pretty emotional, she's the last of her class, she's been one of those ships which work hard.
``Being followed in today by the Type 45 has been pretty special.''
Built by Cammell Laird at Birkenhead, Edinburgh was launched in April 1983 and commissioned in December 1985 and its first deployment was to the Arabian Gulf in 1987, escorting numerous merchant ships safely through the region.
The following year the Duke of York joined as one of the ship's officers, serving on board during a six-month round-the-world deployment.
Other deployments have included the Gulf War in 2003 in which it supported Royal Marines ashore and acted as escort to the helicopter carrier HMS Ocean.
And in 2008 during operations in the Gulf, Edinburgh seized a drugs cargo - stashed on board a sailing boat - worth several million pounds.
Edinburgh's white ensign will be lowered for the final time during a decommissioning ceremony at the Naval Base on June 6.
The Type 42 air defence destroyers have been the backbone of the Royal Navy's fleet since the first - HMS Sheffield - was launched in 1971 and commissioned in 1975. Edinburgh was the 14th and final Type 42 to enter service.
They have served on wide-ranging operations across the globe. Five were involved in the Falklands conflict of 1982 and the three in the Gulf War in 1991. As recently as 2011, HMS Liverpool was ordered to Libya as part of the Navy's contribution to Nato's naval blockade of the country during its civil war.
640 men were killed when the South African troop carrier was hit by a cargo ship in 1917.
The 79-year-old man suffered a serious head injury in the Cranmer Road car park in Winton.
Two Girls Indecently Assaulted Last Sunday
Recently Played Tracks
Now playing: Non-stop hit music
Deposit £10 to get a £40 Welcome Bonus - That's £50 to play bingo, slots and more!*
Over 50 tracks to make you feel-good. New album out now...
Find your local four day weather report here.
What's happening on the roads where you are?
Make Heart the soundtrack to your day and you could be a winner with great prizes up for grabs throughout the day.
Find out more about some of the companies advertising on Heart.
Get some great ideas on how to advertise your business on radio, online and on mobile.