Fine Gael has suffered a drop in support due to the controversy over Tánaiste Frances Fitzgerald's handling of an email about garda whistleblower Maurice McCabe.

The results of the latest Sunday Business Post/Red C poll will be heavily scrutinised by the political parties as the prospect of a Christmas general election looms due to a stand off between Fine Gael and Fianna Fáil over Fitzgerald's future in cabinet.

After a...