Fonblanque was the author of a standard legal work, "Treatise on Equity" (ascribed to Henry Ballow); he was Member of Parliament (MP) for the borough of Camelford following members of his wife's family, Samuel Martin and Sir Ralph Payne.
Fonblanque was the author of the very extensive notes forming the useful body of the standard legal work, "Treatise on Equity" nominally ascribed to Henry Ballow. He was Member of Parliament (MP) for the borough of Camelford 1802-1806 as a member of the Whig party following members of his wife's family, Samuel Martin and Sir Ralph Payne.