This considerably enlarged the electorate, for there had been only 42 voters in the borough in 1816, but the Parliamentary return of 1831 reported that 225 were qualified.
In the 18th century the power of the "patron" to influence the voters in Callington was considered absolute.
[5] The manor and borough were later inherited by the Rolle heiress Margaret Rolle (1709-1765), suo jure 15th Baroness Clinton, wife of Robert Walpole, 2nd Earl of Orford[6] whose son and heir George Walpole, 3rd Earl of Orford (d.1791) died without progeny.
[7] Robert George William Trefusis (1764–1797) successfully claimed the title (17th) Baron Clinton in 1794.
[8] By 1816 it had passed to Robert Cotton St John Trefusis, 18th Baron Clinton but was no longer as secure as it had been, so that the Coryton family was sufficiently influential to challenge his power on occasion.