A by-election need not be held to fill a vacancy in any GRC triggered by the death or resignation of an MP, even if there are no other minority candidates in that GRC, or any other reason. A by-election is required only if all the MPs in a GRC vacate their Parliamentary seats. Assuming that such a situation does arise, the Prime Minister would be obliged to call a by-election within a reasonable time, unless he intends to call a general election in the near future.