City of London

• 1. Introduction

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  The City of London covers just 1.12 square miles. On any given weekday, more than 500,000 people pour into that sliver of ground. At night, fewer than 9,000 remain. This is not a quirk of modern urban planning. It is the result of nearly two thousand years of deliberate choices, ancient privileges, and a governing structure so unusual that it stands apart from every other local authority in the United Kingdom.

  Nicknamed the Square Mile, the City hosts the Bank of England, the London Stock Exchange, and over 500 banks. Its foreign exchange market handled around $1.85 trillion of the daily global turnover in 2009, nearly half of all trading worldwide on that measure. And yet this same patch of ground is governed by a corporation so old that it was never touched by the Municipal Corporations Act of 1835 because its electoral franchise was already wider than the law demanded.

  How did a Roman settlement become the financial capital of the world? How did a city burned twice, bombed into rubble, and nearly absorbed into greater London preserve a medieval system of wards and aldermen into the 21st century? And what does it mean that the residents of this particular square mile carry far less voting weight than the businesses that fill it every morning?

• 2. Roman Roots and Abandonment

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  Roman legions established Londinium on the banks of the Thames around AD 43. A bridge they built across the river, as early as AD 50, near the site of today's London Bridge, turned the settlement into a road hub and a busy port. At its height, Londinium held an estimated 45,000 to 60,000 inhabitants drawn from across the empire, including people from continental Europe, the Middle East, and North Africa.

  Archaeologist Leslie Wallace has noted that extensive excavation has failed to turn up any significant pre-Roman presence at the site, making purely Roman foundation arguments, in her words, "now common and uncontroversial."

  Between AD 190 and 225 the Romans built the London Wall, a defensive perimeter whose course traced a boundary very close to the one the City still observes. The Thames itself was then undredged and wider than it is today, meaning Londinium's shoreline sat slightly north of the current riverfront.

  By the time the wall was finished, trouble had already arrived. Plague and fire eroded the city. Picts, Scots, and Saxon raiders pressed in from outside. The Carausian Revolt shook Roman authority in Britain during the 3rd century. In AD 410 Rome withdrew from Britain entirely. The public buildings fell to ruin. Population drifted westward to a settlement called Lundenwic, roughly in the area now known as Aldwych, leaving the walled Roman city nearly empty.

• 3. Alfred's Gamble

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  In 886 Alfred the Great, King of Wessex, occupied the old Roman walled city and set about making it habitable again. He appointed his son-in-law Earl Æthelred of Mercia to govern it, as part of the broader reconquest of Viking-occupied England. The historian Asser recorded that Alfred "restored the city of London splendidly... and made it habitable once more." The work involved reoccupying the near-deserted Roman streets, building quays along the Thames, and laying down a new street plan.

  Alfred's move had consequences well beyond bricks and mortar. Wessex became the dominant English kingdom. The Viking occupation was, at least partly, rolled back. And the abandoned Saxon settlement of Lundenwic to the west was largely given up, eventually acquiring the name Ealdwic, meaning "old settlement," which survives today as Aldwych.

  In the 10th century, Athelstan permitted eight mints to be established in London, compared with six in his own capital, Winchester. The disparity in minting rights was a signal of the city's recovered commercial weight.

  When William the Conqueror arrived after the Battle of Hastings, he could not force London Bridge and had to cross the Thames at Wallingford. Rather than continue the fight, Edgar the Ætheling and his allies surrendered at Berkhamsted. William granted the citizens of London a charter in 1075. He also built three castles to keep them subdued: the Tower of London, Baynard's Castle, and Montfichet's Tower on Ludgate Hill, which was dismantled and sold off in the 13th century.

• 4. Governance Unlike Any Other

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  Around 1132 the City won the right to appoint its own sheriffs, a power that in every other English settlement rested with the monarch. By 1189 the citizens gained the right to appoint a mayor with the king's consent, and from 1215 they could elect the mayor directly. By 1141 the full body of citizens had been recognised as a single community, which became the origin of the City of London Corporation.

  The Corporation was not reformed by the Municipal Corporations Act of 1835, because it already had a broader electoral franchise than the act demanded. That exemption hardened over time into something stranger still. Today the City is the only local government in the UK where elections do not run on the basis of one vote per adult citizen. Most voters are representatives of businesses operating in the area.

  In the 1630s, when the Crown tried to extend the Corporation's jurisdiction over surrounding areas, the Corporation refused. This "great refusal" is sometimes cited as one reason the City's unique governing structure survived at all.

  The Lord Mayor of London, who heads the Corporation, is not to be confused with the Mayor of London, an office created only in the year 2000. Senior members of the ancient livery companies, the descendants of medieval trade guilds, form the Common Hall, which chooses the lord mayor and the two sheriffs. The sheriffs are described as quasi-judicial offices, appointed by the livery companies rather than elected. The chief executive of the Corporation carries the ancient title of Town Clerk of London.

  The City of London (Ward Elections) Act 2002 doubled the non-resident business franchise from around 16,000 voters to 32,000. Firms employing fewer than 10 people may appoint one voter; those with more than 50 may appoint 10 voters plus one additional for each 50 employees beyond the first 50.

• 5. Fire, Wren, and the Street That Survived

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  The worst fire in the City's history swept through in 1666, though it was not the first time the City had burned badly; a severe fire in 1123 had also earned the name "Great Fire" at the time. The 1666 disaster destroyed the original St Paul's Cathedral completely.

  After 1666, city planners drew up ambitious schemes to remodel the medieval street pattern into a Renaissance grid of boulevards and planned blocks. Almost none of those plans were adopted. The medieval streets re-emerged nearly intact, and that pattern remains largely in place today.

  Christopher Wren's replacement for the cathedral was completed in 1708, on his birthday. The first service in the new building had been held as early as the 2nd of December 1697, more than a decade before the building was officially finished. Wren designed many other City churches in addition to St Paul's, and both the Royal Exchange, founded in 1565 by Sir Thomas Gresham, and Lloyd's Coffee House, established in Lombard Street from 1691, were already transforming the area around Cornhill and Threadneedle Street into the core of a financial district.

  St Paul's also holds an unusual place in the City's height record. From 1710 until 1967, its 111-metre dome was the tallest structure in the City. Its reign of 257 years was ended only by the completion of what is now called CityPoint.

• 6. Bombing and the Skyline It Built

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  Late December 1940 brought some of the most destructive raids of the Blitz to the City. A firestorm that swept through the area on those nights was called the Second Great Fire of London. Swaths of the historic fabric were destroyed, though St Paul's Cathedral survived.

  The destruction created room for a scale of development that older street patterns would never have allowed. The result was a split city: parts not heavily bombed kept their older, smaller-building character, while the most damaged areas were rebuilt with modern large-scale blocks. The Barbican Estate, the main residential section of the City today, was constructed between 1965 and 1976 on land cleared by wartime damage.

  A section of the ancient Roman London Wall, hidden for centuries, was actually uncovered by an air raid on the 29th of December 1940 at the height of the Blitz.

  In 1970 the 600-foot NatWest Tower, at 47 storeys, became the first skyscraper in the UK. The skyline has grown dramatically since. By 2020 the tallest building in the City was 22 Bishopsgate, rising 278 metres across 62 floors. Foster and Partners designed two buildings in the cluster: 30 St Mary Axe, known as the Gherkin, completed in 2003, and the Willis Building, completed in 2007. The tallest structure for the longest unbroken stretch remains Old St Paul's Cathedral, which held the top position from 1310 to 1677, a span of 367 years.

  The IRA's 1993 Bishopsgate bombing prompted the installation of road barriers and surveillance cameras at entry points to the City, a system known as the "ring of steel."

• 7. Money, Power, and Shadow

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  London's foreign exchange market accounted for around 46.7% of the $3.98 trillion global daily turnover measured in 2009. The City of London vies with New York's Lower Manhattan for the title of the world's pre-eminent financial centre, hosting the London Stock Exchange, Lloyd's of London, and the Bank of England, which moved to its present site opposite the Royal Exchange in 1734.

  Many of the world's largest law firms are headquartered in the City, including four of the Magic Circle firms: Allen & Overy, Freshfields Bruckhaus Deringer, Linklaters, and Slaughter & May. In 2009 the City accounted for 2.4% of UK GDP. The Bank of England and the London Stock Exchange sit alongside the insurance industry, which remains concentrated around Lime Street, tracing a direct line back to Lloyd's Coffee House on Lombard Street more than three centuries earlier.

  The City's global reach carries a darker dimension. The financial hub has acquired nicknames such as "The Laundromat" and "Londongrad" because of its role in illicit financial flows. In May 2024, Andrew Mitchell, then the UK's deputy foreign secretary, stated that 40% of the dirty money in the world passes through London and crown dependencies.

  In 2022-12.3% of City of London residents had been granted non-domicile status to avoid paying tax in the UK. The same territory that gave medieval merchants self-governing rights to protect their trades continues to offer arrangements that concentrate wealth and complicate accountability, a tension that has defined the Square Mile since Alfred first relit its streets.