Although a Celtic community settled around a ford across the River Thames, it was the Romans who first developed the square mile now known as the City of London. They built a bridge and an impressive city wall, and made Londinium an important port and the hub of their road system. The Romans left, but trade went on. Few traces of London dating from the Dark Ages can now be found, but the city survived the incursions of both the Saxons and Vikings. Fifty years before the Normans arrived, Edward the Confessor built his abbey and palace at Westminster.

William the Conqueror found a city that was, without doubt, the richest and largest in the kingdom. He raised the White Tower (part of the Tower of London) and confirmed the city's independence and right to self-government.

During the reign of Elizabeth I the capital began to expand rapidly - in 40 years the population doubled to reach 200,000. Unfortunately, medieval Tudor and Jacobean London was virtually destroyed by the Great Fire of 1666. The fire gave Christopher Wren the opportunity to build his famous churches, but did nothing to halt the city's growth.

By 1720 there were 750,000 people, and London, as the seat of Parliament and focal point for a growing empire, was becoming ever richer and more important. Georgian architects replaced the last of medieval London with their imposing symmetrical architecture and residential squares.

The population exploded again in the 19th century, creating a vast expanse of Victorian suburbs. As a result of the Industrial Revolution and rapidly expanding commerce, it jumped from 2.7 million in 1851 to 6.6 million in 1901.

Georgian and Victorian London was devastated by the Luftwaffe in WWII - huge swathes of the centre and the East End were totally flattened. After the war, ugly housing and low-cost developments were thrown up on the bomb sites. The docks never recovered - shipping moved to Tilbury, and the Docklands declined to the point of dereliction. In the heady 1980s, that decade of Thatcherite confidence and deregulation, the Docklands were rediscovered by a new wave of property developers, who proved to be only marginally more discriminating than the Luftwaffe.

London briefly regained its 'cool' reputation in the 1990s, buoyed by Tony Blair's New Labour, a rampaging pound and a swag of pop, style and media 'names'. Blair's blane Ken Livingstone donned the mayoral robes in May 2000, opposing plans to sell off the tube and pushing for improved public transport and safety. The face of the city changed with the construction of the £1bn white elephant Millennium Dome, the London Eye observation wheel, the Tate Modern (linked by the when-will-it-ever-open Millennium Bridge) and the creation of the British Museum's Great Court. But some things never change: London's cost of living outdoes itself year after year, its chic quotient continues to soar and the gap between the haves and have nots looms ever larger.