What really caused the Great Fire of London in 1666 has fascinated historians, Londoners and visitors for centuries. The blaze began in a small bakery on Pudding Lane but soon consumed over four-fifths of the medieval City of London. Understanding what really caused the Great Fire of London in 1666 involves looking beyond just flames and smoke. It means exploring social habits, political tension, architectural flaws and a city waiting for disaster.
What really caused the Great Fire of London in 1666. The spark and the city
Few disasters in European history have been more misunderstood or more symbolically powerful than the Great Fire of London. On that Sunday morning, London was already a city on edge. It had only been a year since the Great Plague of 1665 had killed more than 100,000 people – nearly a third of the population. Public health systems were fragile, and sanitation nearly non-existent. Tensions between Protestants and Catholics ran high. Trade routes were fragile, and London’s wooden core – inherited from centuries of medieval growth – remained untouched by regulation.
At around 1 a.m. on Sunday, 2 September 1666, Thomas Farriner, a baker to King Charles II, locked up his bakery on Pudding Lane and went to bed. Within an hour, his household woke to smoke. By morning, fire had ripped through dozens of homes and began its march across the City of London.
The summer had been dry. Buildings were timber framed and jammed tightly together. Many had thatched roofs despite laws banning them. Narrow alleys acted as wind tunnels. And in a city of over 300,000 people, most water came from buckets.
Eyewitness Samuel Pepys, whose diary became essential reading for this era, wrote on 2 September, “So I made haste home, and then down to the water side, and there got a boat and through bridge, and there saw a lamentable fire. Poor Tom Symons’ house, as well as my own office, all aflame.”
The fire’s spread was helped by strong winds from the east. Sparks jumped streets. Flames leapt across rooftops. Within 24 hours, it became clear that this would not be just another house fire.
Why the Great Fire was inevitable in 1666 London
The City of London in the 1660s was a wooden tinderbox. Of the nearly 13,000 homes in the city proper, over 11,000 were made with timber and tar. Many houses had overhanging upper stories which allowed fire to pass overhead from one street to another without ever touching the ground.
Fires were common. In the first six months of 1666 alone, London saw over 60 major blazes. But nothing matched the scale that unfolded that September.
London’s firefighting system at the time was medieval. Parish churches maintained buckets and fire-hooks. There was no fire brigade. Fire insurance did not yet exist. The main defence was pulling down nearby buildings to create a firebreak, often by hand or using black powder.
Charles II, on 3 September, ordered the use of gunpowder to destroy rows of homes ahead of the blaze. By then, the fire stretched from Tower Hill to the Fleet Ditch.
Misconceptions and forgotten details about the cause of the Great Fire of London
Despite modern consensus about poor urban design and the dry summer, blame flew quickly in 1666. England had recently ended the Second Anglo-Dutch War in July. Anti-Catholic and anti-French sentiment ran high. Rumours spread faster than the fire.
A Frenchman named Robert Hubert confessed to starting the fire by throwing a fireball through a bakery window. He later admitted that he was not even in London when the fire began. Still, a frightened public demanded a culprit. Hubert was tried, convicted and hanged at Tyburn in October 1666.
Historians now agree that Hubert’s confession was false and likely coerced. But the event shows how panic and fear quickly overrode reason.
How far the Great Fire of London reached and what it changed forever
The fire covered an area of 436 acres — roughly one and a half square miles — and destroyed approximately four-fifths of the City of London. Landmarks like the Guildhall, Baynard’s Castle, Newgate Prison, and hundreds of parish churches vanished. Over 100,000 people fled the city, many on boats across the Thames. As refugees spilled into Southwark, Westminster, and beyond, neighbouring towns scrambled to provide shelter.
For days, the air was thick with ash. Charcoal prices skyrocketed. Bread became scarce. Some streets remained impassable for months. Meanwhile, the rebuilding effort gave rise to a generation of architects and masons. By 1675, when construction began on the new St Paul’s Cathedral, over 9,000 temporary wooden structures had already been erected to house displaced residents.
The Great Fire burned for four days and smouldered for nearly a week. It destroyed 87 churches, including the iconic old St Paul’s Cathedral, and reduced over 13,200 homes to ash. Around 70 thousand people were left homeless. Astonishingly, only six verified deaths were recorded, although the true number was likely far higher.
The economic damage was immense. Losses totalled an estimated 10 million pounds in 1666 currency. By comparison, that would be over 2 billion pounds today.
Rebuilding took decades. Christopher Wren redesigned St Paul’s Cathedral along with dozens of churches. Parliament passed the Fire Rebuilding Act in 1667, which required brick and stone construction and widened streets. Fire insurance emerged in the 1680s as a direct result.
What really caused the Great Fire of London in 1666. The deeper reasons history nearly forgot
Although Thomas Farriner’s bakery sparked the fire, the real cause lies deeper. A city built of flammable materials, lacking infrastructure, crowded with homes and businesses, and plagued by poor planning made catastrophe inevitable. It was not just one bakery. It was centuries of risky growth, complacency and urban neglect.
The Great Fire became a turning point. It ended medieval London and gave birth to a more modern, planned city. Yet its causes remind us how disasters often result from many small vulnerabilities combining at the worst moment.
