Below are those MPs who held the seat from just prior to the Restoration onwards.
Due to the town's close proximity to Euston Hall (the main residence of the FitzRoy family), the seat for Thetford has been held by various members of the family: FitzRoy's death caused a by-election.
Due to the triple return, on petition, one vote was knocked off FitzRoy's total and Flower was declared elected in 1842.
Baring succeeded to the peerage, becoming 2nd Baron Ashburton and causing a by-election.
FitzRoy succeeded to the peerage, becoming 6th Duke of Grafton and causing a by-election.