> Just because a system doesn't require something doesn't mean it is legitimate or democratic. It's a personal opinion for sure, but I would call that undemocratic.

I think you risk arguing using a “No true Scotsman” fallacy. There are many forms of democracy, and many countries generally considered democratic don’t require the direct election of their governments leader.

For example the German chancellor is not directly elected. The Dutch prime minister is also not directly elected, neither is the Spanish Prime Minster, or the Prime Minister of Norway. Are they undemocratic as well?

If you look around most long established “democracies”, you’ll find that directly electing the head of government isn’t actual the default.

Indeed the most powerful directly elected politician in the world happens to be the Major of London. They have a surprisingly broad set of powers of a single directly elected politician.

> The PM does have a fairly huge impact on how the country is being run, where it is headed, its foreign policy etc. do you want to argue otherwise?

I most certainly would, as has been quite clearly demonstrated by the long succession of PM the UK has recently had. If the PM is so all powerful, why do they keep failing to get anything done, and keep getting replaced?

> My point is the UK has had multiple PMs in a row who didn't have to make a case for their agenda in front of the people. I call that undemocratic despite what its system says, no system would consider itself authoritarian, that's a judgment passed onto them by 3rd parties.

As a direct consequence of not having to put their agenda in front of the entire UK public, they’ve all failed to achieve anything of note. The only recent PM who could be argued to have achieved anything is Boris Johnson with his signing of the EU Brexit agreement, but he did that after winning a general election!

Every PM since then has been struggling to keep their party together, and struggling to pass anything in parliament, because they lack a strong mandate from the people, and parliament is punishing them for that.

> I think the general expectation in the UK was that this is tolerated because when a new PM comes in, they're expected to win a mandate for their agenda in a general election ASAP.

Until recently this was explicitly illegal. The fixed term parliament act prevented governments from ending their term early and calling an election. Explicitly to prevent the type of abuse that Boris Johnson engaged in, by calling elections when it’s most politically convenient for the government, and thus most likely to result in another win, and an extension to their time in power.

Allowing governments to call elections when it suites them is terrible idea for a democracy. It’s so trivial for the ruling party to abuse.

> A MP running for a local seat is something quite different from being a PM, but anyway this is just one aspect of why I think the UK isn't quite as democratic as it presents itself.

The UK electoral system could certainly use some work. But direct democracies aren’t inherently better. The US uses direct democracy for electing their president, but I’m not sure I would hold up the US as the pinnacle of democracy, not with the endless gerrymandering, political devision, and drive by parties to win at all costs.