[1] He inherited the title of Baron St John of Bletso on the death of his father in 1757.
[1] St John died at the age of 41 at Nice but was buried at Bletsoe.
[1][2] St John married 13 December 1755 to Susanne Louise Simond,[3] the daughter of Peter Simond, a wealthy French Huguenot merchant in London.
[1] The couple had seven children:[3] Their eldest son, John Peter died aged just three and St John was succeeded in the barony successively by his second son Henry and his third son St Andrew.
His widow died at Bath, Somerset in 1805 at the age of 80.