The closure of the city's shipyard, which once kept the British Empire afloat, brings 800 years of power and pageantry to an end.
Everyone knows Britain no longer rules the waves, but we may never be sure of the motives that have kept Scottish shipbuilding in business.
The historic naval city and surrounding area has become vulnerable to big shocks like this and the prospect of new jobs is far from certain.
A march and rally will be held today in a historic naval city to protest at job losses planned by defence giant BAE Systems
Unions said they expect a big turnout in Portsmouth following last month's announcement that shipbuilding is to end with the loss of 900 jobs.
Portsmouth - which has a 500-year history of shipbuilding - will retain repairs and maintenance work.
Unite national officer Ian Waddell said: "BAE Systems' workers, their families and the local community are calling on the Government to think again and secure shipbuilding in Portsmouth for another 500 years."
About 830 jobs will also be lost at yards in Govan and Scotstoun, on the River Clyde in Glasgow, at Rosyth in Fife, and at the firm's Filton office, near Bristol, as a result of a drop in work after the end of aircraft carrier work.
A new version of the one of the world’s leading combat aircraft has taken its first flight at the RAF base in Warton, Lancashire.
The latest standard of the Eurofighter Typhoon, known as Tranche 3, will be flown by the RAF and other air forces for years to come.
BAE Systems, which built the aircraft, said the jet was “future proofed” to take on new technologies and would create jobs for thousands of defence workers.
The Typhoon, which has been exported to Austria, Saudi Arabia and Oman, was first used in combat during the 2011 military intervention in Libya.
Around 200 people joined a rally to protest BAE's announcement that it is to stop shipbuilding in Portsmouth.
Many demonstrators carried placards to support workers at the shipyard, where 940 jobs are expected to go if BAE goes ahead with the proposed closure of the site next year.
Mike Hancock, the MP for Portsmouth South, was at the city's rally today. He was there to support demonstrators hoping to save 940 BAE jobs. The cuts were announced earlier this week.
The heavy blow of hundreds of job losses in Scottish shipbuilding has been softened by the announcement of new contracts that will keep operations in Govan going for more than two decades.
Scotland Correspondent Debi Edward reports on the response from the shipbuilders on a decision that politically protects those campaigning against Scottish independence ahead of next year's referendum.
Labour leader Ed Miliband has said he does not believe the Scottish referendum played a part in the decision to continue shipbuilding in Scotland while closing the Portsmouth yard.
Mr Miliband supported the Government in its claim that the retention of Scottish jobs was for defence reasons only.
The leader of Portsmouth City Council has said the decision to shut down the city's shipyard, which is the only one in England able to build advanced surface warships, smacks of politics.
– Council leader Gerald Vernon-Jackson
The remaining yards with the capability to build advanced warships are in Scotland, and the referendum on Scottish independence is less than one year away. Ministers have put the defence of the UK and the future of the Navy at real risk.
Portsmouth Conservative councillor Alistair Thompson added: "Many of those who I represent as a councillor are hugely concerned that this decision has been taken for political reasons because of the referendum in Scotland next year."