Bonfire Night History: The Gunpowder Plot Investigation

By the early 17th century, England had lived through generations of religious whiplash: Henry VIII’s break with Rome, Edward VI’s Protestant reforms, Mary I’s restoration of Catholicism, and Elizabeth I’s Protestant settlement. Religion was no longer private belief — it was tied to loyalty, foreign alliances and national security. English Catholics lived under legal restrictions, and some hoped the next monarch would ease them.

Those hopes rested on James VI of Scotland, who became James I of England in 1603. Relief never came in the way some Catholics expected, and the political and religious environment remained deeply divided. Most English Catholics never turned to violence. A small circle around Robert Catesby concluded that peaceful change would not work.

In May 1604, Robert Catesby gathered a small circle that came to include Thomas Winter, John Wright and Thomas Percy. Their objective was extraordinary: destroy Parliament during the State Opening, when the King, the royal family, the Lords, the Commons, bishops and judges would all be gathered in one building. A second phase followed the first — while London descended into chaos, conspirators in the Midlands hoped to seize Princess Elizabeth, James I’s young daughter, and trigger a wider Catholic uprising. The assassination plan was detailed. What would happen to the country afterward was far less developed.

Guy Fawkes had spent years abroad and had real experience with weapons and explosives — exactly what the conspirators needed. He was recruited as the group’s gunpowder expert and adopted the alias “John Johnson,” posing as Thomas Percy’s servant, an identity that became critical the moment he was arrested. The traditional account holds that the conspirators first attempted to tunnel toward the House of Lords, but the work proved difficult. Then an easier opportunity appeared: a storeroom directly beneath the chamber became available to rent. In March 1605, Thomas Percy secured that undercroft, and the conspirators began moving in gunpowder — eventually 36 barrels, concealed beneath firewood, with the King, the Lords, the bishops and the judges due to sit directly above.

Parliament’s State Opening was delayed several times, which created its own problem: gunpowder can deteriorate, plans have to be maintained, and every month of secrecy meant more people had to be brought in — and every additional person was another possible leak. Eventually Parliament was scheduled to open on 5 November 1605, giving the conspirators a fixed deadline.

Lord Monteagle was at his house when a servant delivered a strange, anonymous letter. It advised him to stay away from Parliament, warning obscurely that the sitting would receive “a terrible blow” and that those responsible would not be seen. Monteagle did not dismiss it — he took it directly to Robert Cecil, Earl of Salisbury, the King’s principal minister. It became the investigation’s first major clue, though more than four centuries later, its author is still unknown.

The government did not raid immediately. Robert Cecil was informed, King James returned from a hunting trip and was shown the letter, and officials worked to interpret the word “blow” — the King reportedly connected it to gunpowder, turning attention to the buildings around Parliament. On 4 November, the Lord Chamberlain inspected the areas near the House of Lords and noticed a suspiciously large pile of firewood, guarded by a man who gave his name as “John Johnson.” Nothing decisive happened at first, but the report went upward, and a second, more thorough search was ordered.

Around midnight, Sir Thomas Knyvett led that second search. Beneath the firewood, officials found 36 barrels of gunpowder and materials for igniting them. Guy Fawkes was arrested on the spot. Parliament was hours from opening.

On learning Fawkes had been captured, the remaining conspirators fled London for the Midlands, still hoping to trigger the uprising. They stole horses and contacted sympathisers, but the rebellion never became a mass movement — Parliament’s own account puts support at no more than around 50 people, who soon dispersed. Exhausted and wet, the fugitives reached Holbeach House in Staffordshire, still carrying gunpowder. Attempting to dry some of it by a fire, they accidentally ignited it, injuring several of the men — the conspiracy that planned to destroy Parliament with gunpowder was now damaged by its own.

Local forces surrounded Holbeach House on 8 November. In the confrontation that followed, Robert Catesby, Thomas Percy, John Wright and Christopher Wright were killed. Others were captured. The plot’s central organiser would never stand trial — the government’s public case would rest on confessions, documents and the men who survived.

Under torture, Fawkes’s initial composure gave way to fuller confessions; surviving signatures show his handwriting visibly deteriorating across the interrogation period. Eight surviving conspirators were brought to Westminster Hall on 27 January 1606 and convicted of high treason. The investigation also widened toward the Jesuit priesthood — whether senior Jesuit Henry Garnett knew of the plot, and whether knowledge received through confession could be disclosed. Garnett was tried separately and convicted.

The story does not end with the executions. In 1606, Parliament passed legislation establishing 5 November as an annual day of thanksgiving for deliverance from the plot. Church services, bells and bonfires followed; fireworks and burning effigies came later. Early commemorations did not always centre on Guy Fawkes — effigies of the Pope and the devil were burned in some periods, reflecting the era’s anti-Catholic sentiment, which the plot’s failure sharply intensified. Over time, Fawkes became the fixed figure of the tradition, and children traditionally build a “guy” for the bonfire. The legally required observance ended when the Thanksgiving Act was repealed in 1859 — by then the tradition no longer needed Parliament’s instruction to survive.

For centuries, alternative theories have circulated: did Robert Cecil know about the plot earlier than he admitted? Was the Monteagle Letter itself manipulated? Was the whole affair allowed to develop in order to justify harsher policies against Catholics? These make excellent mystery stories, but historical caution is essential. There is evidence the government had some awareness of suspicious activity before the final discovery, and there are genuinely unresolved questions around the Monteagle Letter’s authorship — but there is no conclusive surviving evidence that the plot was invented or orchestrated by the government. The responsible conclusion is that questions remain, not that a conspiracy is proven.