Parliamentary Oaths Act 1866

5Penalty for Omission to take Oath.

If any Member of the House of Peers votes by himself or his Proxy in the House of Peers, or sits as a Peer during any Debate in the said House, without having made and subscribed the Oath hereby appointed, he shall for every such Offence be subject to a Penalty of Five hundred Pounds, to be recovered by Action in One of Her Majesty's Superior Courts at Westminster ; and if any Member of the House of Commons votes as such in the said House, or sits during any Debate after the Speaker has been chosen, without having made and subscribed the Oath hereby appointed, he shall be subject to a like Penalty for every such Offence, and in addition to such Penalty his Seat shall be vacated in the same Manner as if he were dead.