Comment by amiga386

You will find that written constitutions are about as effective as unwritten ones; if the people in power choose to disregard them, and have popular support, they tend to get away with it for long enough to do damage.

Fun fact: The UK has the Magna Carta, the original bill of rights signed in 1215. Did you know that's 561 years before the US declared its independence from the UK? To put it another way, 561 years is more than double the length of time the US has been a country.

Second fun fact: UK Prime Ministers aren't elected. Their party is elected, and tends to command a majority in the House of Commons, but if they don't, they get to trade horses with other parties to see which coalition can command a majority, and thus win a confidence vote. The party selects a leader through their own internal processes. Doesn't even have to be an elected MP. Then they tell the king, who rubberstamps the decision. They can do this at any time, not just after an election. Provided the leader can command a majority in Parliament, they get to continue. If enough of your own party dislikes you as leader, they will vote against a confidence motion and drop themselves and you out of power; your job is to not let it get to that.

The House of Lords is a secondary chamber, which scrutinises what the House of Commons passes and suggests rewordings and rewrites. (There's a whole other layer of scrutiny at the committee stage, for costing, etc.) They can send back bad bills, but can't send them back indefinitely, if the government had that in its election manifesto, so appointed or not, they can't defy the "will of the people".

The king doesn't rock the boat, not because he fears for his life, but because he'd trigger a constitutional crisis which will inevitably resolve in the form of a republican UK.