Portsmouth () is a port city primarily built on Portsea Island in the county of Hampshire, South East England. It is also known colloquially as Pompey, a nickname shared with HMNB Portsmouth and the Portsmouth Football Club. It is the United Kingdom’s only island city. Portsmouth is situated 70 miles (110 km) south-west of London and 19 miles (31 km) south-east of Southampton. Portsmouth’s population was recorded as 205,100 in the 2011 UK Census. The city forms part of the South Hampshire conurbation.

Portsmouth’s history can be traced back to Roman Britain. A significant naval port for centuries, it has the world’s oldest dry dock. Portsmouth was England’s first line of defence during the 1545 French invasion. By the early nineteenth century, the world’s first mass-production line was set up in Portsmouth Dockyard’s Block Mills; this made it the world’s most industrialised site, and the birthplace of the Industrial Revolution. Portsmouth was the most heavily-fortified town in the world and was considered “the world’s greatest naval port” at the height of the British Empire, during the Pax Britannica. The Palmerston Forts were built around Portsmouth in 1859 in anticipation of another invasion from continental Europe.

King Richard I first granted Portsmouth market town status on 2 May 1194 with a royal charter and a coat of arms, “a crescent of gold on a shade of azure, with a blazing star of eight points”. On 21 April 1926, Portsmouth was elevated from town to city status. Its motto, “Heaven’s Light Our Guide” (referring to the city’s eight-pointed star and crescent-moon emblem), was registered in 1929. The 800th anniversary of the royal charter was celebrated on 2 May 1994. Portsmouth became a unitary authority on 1 April 1997, with its city council gaining the powers of a non-metropolitan county and district council previously held by Hampshire County Council.

The city was extensively bombed in World War II’s Portsmouth Blitz (which resulted in the deaths of 930 people), and was the pivotal embarkation point for the 6 June 1944 D-Day landings. In 1982, a large proportion of the task force dispatched to liberate the Falkland Islands deployed from the city’s naval base. Her Majesty’s Yacht Britannia left the city to oversee the 1997 transfer of Hong Kong which, for many, marked the end of the British Empire.

HMNB Portsmouth, considered the home of the Royal Navy, is the base for two-thirds of the UK’s surface fleet. The city has a number of famous ships, including HMS Warrior; the Tudor carrack Mary Rose, and Horatio Nelson’s flagship HMS Victory (the world’s oldest naval ship still in commission). The former HMS Vernon naval-shore establishment has been redeveloped as the Gunwharf Quays retail park. Portsmouth is among the few British cities with two cathedrals: the Anglican Cathedral of St Thomas and the Roman Catholic Cathedral of St John the Evangelist. The waterfront and Portsmouth Harbour are dominated by the Spinnaker Tower, one of the United Kingdom’s tallest structures at 170 metres (560 ft). Southsea is a seaside resort with an amusement arcade on Clarence Pier.

Portsmouth F.C., the city’s professional football club, play their home games at Fratton Park in Milton. Portsmouth has good road and rail links to London and the south of England. Portsmouth International Port is a commercial cruise-ship and international ferry port. It is the UK’s second-busiest port (after Dover), handling about three million passengers a year. The University of Portsmouth has a student population of 23,000. Portsmouth is the birthplace of author Charles Dickens, engineer Isambard Kingdom Brunel and former Prime Minister James Callaghan.