The Monteagle Letter
On 26 October the plot was compromised after an anonymous whistleblower sent a letter to the Lord Monteagle, informing him that there would be ‘a great blow this parliament’ and that he should avoid attending. Fearing its significance, Monteagle passed the letter on to Sir Robert Cecil who later showed it to the king. Despite becoming aware of the letter, Catesby pressed on. He instructed Guy to check the cellar and search for any sign that they were under threat. On seeing no harm, Guy returned with the news Catesby hoped for. Despite Catesby using him for such a potentially dangerous task Guy’s loyalty to Catesby remained undiminished and the plot would go ahead.
On 3 November the conspirators, now numbering 13, made arrangements for the execution of the plot. On 4 November, Guy made preparations for the lighting of the gunpowder, following which he would travel to Flanders to spread news of the destruction. On that day Guy was seen in the cellar by government officials. Despite paying him little attention, a second search was ordered. With hours to go before lighting the match, a planned search of the vaults saw Guy Fawkes arrested.