Passage: The Lords Chamber is the site of nationally televised ceremonies, the most important of which is the State Opening of Parliament, which is held formally to open each annual parliamentary session, either after a General Election or in the autumn. At this occasion every constitutional element of the government is represented: the Crown (both literally, and figuratively in the person of the Sovereign), The Lords Spiritual and Temporal, and The Commons, (who together form the Legislature), the Judiciary (although no judges are members of either House of Parliament), and the Executive (both Government Ministers, and ceremonial military units in attendance on the Sovereign); and a large number of guests are invited to attend in the large Royal Gallery immediately outside the Chamber. The Sovereign, seated on the Throne, delivers the Speech from the Throne, outlining the Government's programme for the year and legislative agenda for the forthcoming parliamentary session. The Commons may not enter the Lords' debating floor; instead, they watch the proceedings from beyond the Bar of the House, just inside the door. A small purely formal ceremony is held to end each parliamentary session, when the Sovereign is merely represented by a group of Lords Commissioners.

Question: What important ceremony does every member of government participate?
State Opening of Parliament