I remember long and fruitless, yet highly enjoyable, arguments with a friend on this one: if we have a constitution but it's not written down anywhere how do we know what it says? If we do know what it says then it can be written down.

If it can't be written down how could it enter as a factor in any legal proceedings?

Worth the paper it's not written on IMO.

    A: "You can't do that it flouts the UK constitution"
    B: "Oh right, what's the constitution say?"
    A: "Well, I can't tell you that ..."

It is written down, in 800 years of case law and legal decisions.

It's just a little more complicated than a few cliches about "all men being equal" written by slave owners

Sorry but that's from the Declaration of Independence. By the way, those clichés were not clichés when they were written -- that's why they were so revolutionary at the time. England certainly didn't recognize individual rights at the time. Dismissing the Constitution and the Declaration as a few clichés is to reveal an ignorance of the historical context of those documents.

Additionally, The British had slavery until 1833 -- slavery wasn't an American invention. Disparaging the paradox of slave owners writing all men were created equal is also revealing as to a lack of understanding of history and the context in which those documents were created as well as the political realities at the time.

Stick to code, your historical snark makes you look foolish.

So English (UK?) constitution === stare decisis with common law?

That of course makes the constitution unknowable because the supreme court, the House of Lords, can ignore precedent. So that still leaves us with no way to know the constitution the best we could hope for is to form a quorum of Lords and check that something is legally OK with them; even then they could changed their minds.

I still think that without a clearly defined and codified set of basic principles a nation doesn't have what I would call a constitution.

In practice I'm not sure it makes much difference.

Mostly constitutions, charters of rights and freedoms, or whatever are full of wonderful phrases about mankind. Especially if you get somebody good like Thomas Paine to write it. But it's the courts that decide if abortion is allowed and reject claims that smoking bans go against magna carta.

There are also administrative uses - the constitution sets down how often elections happen and who succeeds who. But if you are a 'nice' country that abides by that constitution then you would also presumably abide by the historical convention that the Queen picks the prime minister with the most seats in the house - even if that isn't written down.

If McArthur had decided to seize Washington in a military coup then a Constitution isn't physically going to stop him (that's what the marine corp is for!)

Similarly in Russia the new democratic constitution stopped Putin serving another term - but it didn't stop him putting a puppet in place.