The House is up. The business of the day is ended, and the
members may rise up from their seats and go home.
A.B. is up.
A.B. is on his legs, in for a speech. “Up, Guards, and at them!” Creasy, in his Fifteen Decisive Battles, states that the Duke of
Wellington gave this order in the final charge at the battle of
Waterloo. It has been utterly denied by recent writers, but it is the
fashion to deny or discredit all cherished traditions. I, for one, wish
the tradition were true, because, like Nelson's mot at Trafalgar, it
gives a memorable interest to the charge; but alas! we are informed
that it was not the Guards, but the 52nd light infantry which broke the
column of the French Imperial Guard in the final charge, and “honour to
whom honour is due.”
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894