Our legal and government system isn't directly analogous to, for example, the separation of powers that exists in the US. The House of Commons consists of elec

Our legal and government system isn't directly analogous to, for example, the separation of powers that exists in the US. The House of Commons consists of elected MPs, and forms our primary legislative body. The typical process is for legislation to originate in the Commons where it's brought forward by the government of the day, go through various stages where it bounces back and forth between the Commons and the House of Lords, and then become law when it receives royal assent. The latter is almost entirely a formality these days, and while the Lords can and routinely does propose amendments to laws and can delay laws it isn't happy with, ultimately the Commons can overrule them if it really wants to. Various other possibilities for originating legislation exist, but they are rarer, and the Commons still ultimately wins disagreements if it chooses to. Our administrative/executive government is not independently elected, but rather a Prime Minister is selected to form it. The PM is almost always the leader of a party that can command the support of the Commons, either with an outright majority for their party in its own right or through some sort of coalition or other partnership agreement. Consequently, the PM is usually an MP themselves. They then select, normally from among MPs and Lords, other people to form a Cabinet and take on the various senior positions in the government. In principle, the holders of these posts are all servants of the Crown for traditional reasons, but again that is essentially a formality today. Aside from its direct legislative duties, Parliament (the Commons and Lords) also conducts a lot of work in committees like the one we're talking about today; arguably, this is where most of the real work actually happens, since these committees often provide the detailed scrutiny of new proposed legislation within their field as well, but more generally the work of the committees may guide both legislation and the actions of the government (that is, the executive/administrative element led by the PM). In short, MPs are really the heart of our system of government, and being awkward when a parliamentary committee invites you to attend is not going to end well.