Two years later he became president in a fixed election.

ECONOMIST: Nguyen Van Thieu

It would not be possible to implement fixed-term parliaments if a general election could be called by a simple majority in the House of Commons, he said.

BBC: Two-thirds dissolution rule 'is dangerous' - Tory MP

To avoid allowing a "zombie government" to stagger on for years, unable to muster a majority to pass any new laws, the Fixed Term Parliaments Bill, says an election will be called 14 days after a lost confidence vote if no alternative government is able to show they have the confidence of MPs.

BBC: Q&A: Fixed term parliaments