Suspected of plotting to kill William III, he was held in Newgate Prison without trial for fifty years, eventually dying in 1748.
Acts extending their imprisonment were passed at the start of each succeeding monarch's reign, although one man, Captain James Counter, was released by Queen Anne.
[6] The History of the Press-yard, a 1717 pamphlet claiming to have been written by a Jacobite held in Newgate, briefly describes the five imprisoned plotters including a likely reference to Blackbourn as "a Man of Pleasure [...] who had never been known to have entertain'd a melancholy Thought since his entrance into the Gaol".
[7] Later in the pamphlet "Mr Bl[ackbour]n" is asked to draw a plan of a bridge leading over the River Ribble on news of the Jacobite advance on Preston.
[10] The Irish mercenary soldier Captain Peter Drake, who had spent time in Newgate and often visited the surviving plotters in the Pressyard there, states in his memoirs that "Blackburn I last saw in April, 1745, he was then in the Press-yard, and well and as hearty as ever.