While many parliaments round the world these days have electronic voting systems, the oldest of them all retains its system of physical divisions, whereby MPs file into an 'aye' lobby if they agree with a motion or Bill, or a 'no' lobby if they disagree.

Here, backbenchers can mingle with government ministers and use the chance to speak to them on a particular issue.

When MPs vote, they must give their names to the clerks at the desks at the end of the lobbies, who tick their names off the roll.

Tourists do not visit the Ayes' Lobby.