In the summer of 1784, it was reported that Pitt was nearly shot by a farmer/gardener in Wandsworth, greater London:
"The circumstance was shortly as follows: Mr. Pitt dined that day with Mr. Jenkinson, and returned to town in a post carriage; but the boy blundering out of the main road, and not being able to find his way back, Mr. Pitt was induced to go to the next farm-house, to be rightly informed. The dogs, however, making an alarm, the man of the house came out with a loaded gun, and insisted on Mr. Pitt's standing still, on pain of being fired at. Mr. Pitt pleaded and expostulated in vain, till at length the farmer actually fired at him; and the bullet went through the loose part of his [Mr. Pitt's] coat, but happily without doing any injury. The post-boy, hearing the explosion, ran to the spot; and his appearance, together with Mr. Pitt's arguments, at length so far prevailed on the farmer, that was chancellor [Pitt] was permitted to withdraw; and his antagonist gave him every necessary instruction to find out the main road to town. 
Now, before you start thinking that the story is a load of hogwash, it was actually reported in several August 1784 newspapers, including this report in the Oxford Journal of Saturday, 21 August 1784:
"On Tuesday night [17th August], the Right Hon. William Pitt narrowly escaped being shot by a Farmer near Wandsworth."  The same 'circumstance' is given, but the report goes on to add that "according to another account, Mr. Pitt is said to have been on his Return from a visit to Mr. Dundas." 
Dundas was then living at Warren House, in Wimbledon, and Pitt would have most likely had to travel through Wandsworth in order to return to Downing Street. Pitt was also renting a house on Putney Hill in 1784, however presumably he was headed back to town that night. He had only become First Lord of the Treasury the previous December, and it is highly fortunate that his life was preserved just as he was embarking on his premiership!
1. Huish, R. (1821) The public and private life of His late Excellent and Most Gracious Majesty, George the III. London: Thomas Kelly, p. 438.
2. Oxford Journal, 21 August 1784.