With the aristocracy dominating the House of Lords, the Senate represents the common people.
The Upper House is the House of Lords, which likely represents the interests of the aristocrats, while the Lower House is the Senate, and the Senators may be drawn from their State Legislatures. Britannia appears to be an absolute monarchy, meaning that the Royal Family holds most or all authority and administrative power, though there is also a bicameral legislature in effect, at least in the Britannian Homeland (The Capital World is called the 'Homeland').
