Who runs Britain? Once, the answer would certainly not have been Members of Parliament. Perhaps it still isn't.
Nevertheless, the relative importance of MPs has increased dramatically since the days when the Commons used to meet in Westminster Abbey refectory, playing second fiddle to their aristocratic overlords in the upper chamber, who themselves knew that real power was wielded by the monarch alone.
But MPs have been able to see off their historical rivals in the battle for the controls in the cockpit of the nation.
The House of Commons now has the final say on the content of legislation produced by Parliament - its ability to over-rule the Lords was enshrined in law at the turn of the 20th Century.
And yet, the quality of debate in the lower chamber (as it's called, despite its all-powerful status) oscillates suddenly and violently: at times peppered with insightful rhetoric and lofty oratory; at others degenerating into a rowdy shouting match, rather like a playground clash between rival gangs of schoolchildren whose favourite jibes are "Shame!" and "Resign!".
Rowdy scenes are not rare
The Speaker, whose daunting task it is to keep order in the chamber, enforces a set of rules that may seem archaic, but which reflect an ancient logic.
MPs are not allowed to call each other "you", or even invoke their colleagues' names; they refer to each other instead as "honourable members", individually identifiable only by the name of their constituency.
If an MP implies that a colleague is dishonourable, or guilty of deliberately telling untruths to the House, or is drunk, he or she may be thrown out of the chamber.
Cut and thrust
However, claiming that a fellow MP has "inadvertently" misled the House is quite acceptable, and, thanks to parliamentary privilege, an MP can never be charged with slander for anything he or she says in the chamber, no matter how damaging it may seem to the individual implicated, or how baseless the allegation.
And fortunately for the Speaker, the House was designed so that rival parties would sit on opposite rows of benches positioned precisely two sword-lengths apart to prevent things getting out of hand.
The lower chamber fought for centuries to gain the upper hand in the UK's constitutional settlement, and yet MPs voted in 1998 to rescind an enormous amount of its power.
Devolution means that MPs have no influence at all on decision-making on a wide range of policy areas in vast swathes of the kingdom, where the devolved institutions in Scotland, Wales and Northern Ireland now rule the roost.
There are 650 MPs in total
Each MP represents the residents of a constituency in the UK
MPs are paid a basic salary of £65,738, with additional compensation for those who become ministers
Most senior ministers are elevated from the ranks of governing party (or parties) MPs - although some are peers
Some MPs work on select committees, where they carry out detailed scrutiny of government policy
The House typically sits from Monday to Thursday in term time, with some Friday sittings
The Commons often does not sit on a Friday so that MPs can work on constituency business
Parliament began convening regularly in Westminster in the 13th Century to approve the monarch's tax plans
It takes its name from the French parler, meaning to speak - via parlement, or discussion
By the mid-14th Century a bicameral system emerged, meaning that the Commons and Lords meet separately
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