[2] Magnay was the son of John Magnay and Ann Liddle of Haltwhistle, Northumberland, where he was baptised in October 1767.
[3] He was a City of London merchant and a member of the Worshipful Company of Merchant Taylors.
In 1809, he was elected an alderman of the City of London for Vintry ward.
In 1821, he was elected Lord Mayor of London.
[4] Magnay was the father of William Magnay, who was also Lord Mayor of London, in 1843, and became a baronet.