Admiral of the Fleet, The Rt Honourable Sir George Cockburn Bt [1772-1853] who was promoted such in July 1851 at the age of 79,  is recorded as a young officer as being a fierce fighter and a strict disciplinarian. He hated and fought the French with great vigour and by the time of Trafalgar, George Cockburn was aged 33 and had seen much action. Early on, Cockburn and his first lieutenant, one Thomas Masterman Hardy, became good and firm friends with Hotatio Nelson. Part of that action had been to support the French Royalists against the French Republicans  in the early days of the French Revolution, and in 1793, one year before the first big sea battle of the Napoleonic Wars [the Glorious First of June in 1794] he was in the thick of it in the South of France, at the Port of Toulon. During that battle, known as the Siege of Toulon, a French navy ship belonging to the State and thus to the King of France, King Louis XVI, deserted the Port and the French Royal cause, and with the captain and full crew aboard, sailed away heading for the safety and the friendship of Royalist Britain.  After many weeks the ship arrived at the safe anchorage of Spithead off Portsmouth, and the captain,  Captain Poulain handed over his ship to the Royal Navy.

The French ship's name was Pompée and George Cockburn was one of its commanding officers in 1808/9 - see The British Admirals of the Fleet ISBN 0 85052 835 6 by T.A. Heathcote Published in 2002 pages 47 to 51, 302 inter alia.

The area now commonly known as Portsmouth, was commonly known as Portsea in the 18th century, and having a French ship in their midst was intriguing.  Remember at this time Napoleon was strutting around southern Europe as a young French officer and his name was largely unknown.  Apart from vying with the French for trade, there was precious little to hate the French for. Moreover, the stories reaching Britain about the terrors of republican gangs roaming French streets was enough to stimulate pity for the French and no doubt they felt pity for these French sailors now occupying hulks along with paid-off Royal sailors in Portsmouth's dockyard. 

F.S. Pompée was commissioned as HMS Pompee, and spent many years fighting the French Republican navy, both in north west European waters and in the Caribbean, where, in 1809 and in 1810 she won Battle Honours at Martinique and Guadeloupe respectively - see Battle Honours of the Royal Navy Published by Maritime Books of Liskeard Cornwall in 2004, page 164.   The design of the French ship was copied and a British class of ship called the 'Pompee Class' [two ships, the Superb and the Achilles] were built which were very effective in the last of the Napoleonic Sea Battles of 1812, fought against the USA and their ally, France.

After the Battle of Waterloo in 1815 when Napoleon was captured and incarcerated, HMS Pompee, unwittingly and unintentionally, started a reign of terror, which used the very name of the ship as a byword for fear. From 1816, she became the chief PRISON SHIP anchored in Portsmouth harbour, and Pompee [Pompey] signified a place to be avoided at all cost.  Being press-ganged was preferable to a visit to the Pompee. In my time in the Service, the word Colchester [being the Army-run tri-service correction centre in that City in Essex] put the same fear into one, and I also remember well that the word Dartmoor was more to do with the notorious prison there than it was to do with the bleak and rugged tors.

However, the national fear of Pompee was soon overtaken by elation, for, by 1817 it was being used as the Prison Ship for French prisoners-of-war, and they adopted that fear of the ship in great measure, many trying to commit suicide in their induction period when not being held in chains. After a time of brutal and harsh treatment, 'established' prisoners were used ashore as forced labourers.  More and more hulks were used to accommodate French prisoners-of-war and they kept on coming from the European mainland for many years after their defeat. They, but not HMS Pompee, were still in the area in 1824 when the Forts around the area were started, but their completion was many years later in 1860, undertaken by many hands some prisoners-of-war [from the Crimean War] some domestic prisoners and many artisans, on the orders of Lord Palmerston leading them on to being called Palmerston's Follies, for they were never used in anger.

This is a part of the original Admiralty ships drawings [now archived in the National Maritime Museum at Greenwich] of the Pompee, drawn in Portsmouth Dockyard in 1794 at the time of its complete overhaul to become a British ship.

Scale: 1:48. Plan showing the body plan, stern board outline with decoration detail and the name in a cartouche on the stern counter, sheer lines with inboard detail and figurehead, and longitudinal half-breadth for Pompee (1794), a captured French Third Rate, as taken off at Portsmouth Dockyard prior to fitting as a 74-gun third Rate, two-decker. Signed by Edward Tippet [Master Shipwright, Portsmouth Dockyard, 1793-1799]. Date made 26th August 1794 Portsmouth Dockyard

As time went by, the old Pompee was seen as a friend, punishing the French on a daily basis for the British war losses both at sea and on terra firma.  It began to be spelt as Pompey and eventually the whole of Portsea Island was known as Pompey.  Pompee was a novelty, a surrendered foreign warship, then a British naval fighting vessel winning battle honours and finally a long serving prison ship, and she had been on the tip of local peoples tongues for many a long year. The word grew on Portsea and it became an endearment and the name of POMPEY has stuck with the City ever since.

Post script.  Sir George Cockburn went on record an an Admiral of the Fleet, saying that after the introduction of steam vessels into the navy, he never saw a clean deck nor was waited upon by a captain who did not look like a sweep.

See also these pages on this and other naval ports:-

THE_PLYMOUTH_COMMAND
where has it all gone?
A stunning picture of Portsmouth Dockyard - pity about the ships !
1958 naval cuts
CHATHAM DOCKYARD
DEVONPORT DOCKYARD OVERALL
DEVONPORT DOCKYARD NORTH YARD