On 26 October 1605 Hoxton achieved notoriety, when a letter arrived at the home of local resident
William Parker, Lord Monteagle warning him not to attend the
Parliament summoned by
James I to convene on 5 November, because "yet I say they shall receive a terrible blow, the Parliament, and yet they shall not see who hurts them".
The letter may have been sent by his brother-in-law
Francis Tresham, or he may have written it himself, to curry favour.
The letter was read aloud at supper, in front of the company of prominent Catholics, and then he brought it personally to
Robert Cecil at
Whitehall. While the conspirators were alerted, by the public reading, to the existence of the letter they persevered with their plot as their gunpowder remained undiscovered.
William Parker accompanied
Thomas Howard, the
Lord Chamberlain, in his visit to the undercroft of parliament, where
Guy Fawkes was found in the early hours of 5 November.
[11] Most of the conspirators fled on the discovery of the Gunpowder Plot, but
Francis Tresham was arrested a few days later at his house in Hoxton.
A commemorative plaque is attached to modern flats on the site of Parker's house in Hoxton Street.