A friend asked me about the role of the Speaker in the event of a hung Parliament and in particular what the Speaker does if there is a tied vote. He assumed the Speaker would normally vote with the Government.
If there is a tied vote, the Speaker exercises a casting vote. Formally, he is free to vote as he wishes without giving a reason. However, in order to avoid any impression of partiality, he normally follows precedent. Three basic principles have emerged from how Speakers have utilised their casting votes in the past:
1. That the Speaker should always vote for further discussion where that is possible.
2. That where no further discussion is possible, decisions should not be taken except by a majority.
3. That a casting vote on an amendment to a Bill should leave the Bill in its existing form.
These principles have emerged despite the fact, as noted in Erskine May, that successive Speakers have not always been consistent.
In the Lords, there is no casting vote. The occupant of the Woolsack has an original vote but not a casting vote. If a vote is tied, the outcome is determined by Standing Order, which essentially states that a motion is rejected unless there is a majority in its favour.