... so explain Crown prerogative in the UK then.

(and don't tell me the UK has no constitution - it has no unified, codified constitution, but it sure as hell has one)

The United Kingdom (and more specifically, England) is an exception. Actually, I had the United Kingdom in mind when I've said "most". The system of the government of the United Kingdom is exceptionally complex and in theory it is still ruled by the Sovereign by the Grace of God. In practice though, the Royal Prerogative is exercised by the Crown and not the Sovereign, which means the Government which is lead by the Prime Minister who is in turn the leader of the parliamentary majority which is elected by the people.

Well, here's a potentially-relevant quote from the North Korean constitution:

Comrade Kim Il Sung elucidated the fundamental principles of nation building and State activities, established the best State and social system, the best mode of politics and system and methods of administering society, and laid solid foundations for the prosperity of the socialist motherland and for the continuation and consummation of the revolutionary cause of Juche. Regarding “The people are my God” as his maxim, Comrade Kim Il Sung always mixed with the people, devoted his whole life for them and turned the whole of society into a large family which is united in one mind by taking care of the people and leading them through his noble benevolent politics. The great leader Comrade Kim Il Sung is the sun of the nation and the lodestar of national reunification.

Here's another:

As a veteran statesman in the world, Comrade Kim Il Sung opened up the new era of independence, carried out energetic activities for the strengthening and development of the socialist movement and the non-aligned movement as well as for world peace and for friendship among the peoples and made an imperishable contribution to the cause of human independence. Comrade Kim Il Sung was a genius in ideology and theory, a master of leadership, an ever-victorious iron-willed brilliant commander, a great revolutionary and politician and a great man.

And one more for the road:

Article 4. The sovereignty of the Democratic People’s Republic of Korea resides in the workers, peasants, working intellectuals and all other working people. The working people exercise power through their representative organs―the Supreme People’s Assembly and local People’s Assemblies at all levels.

Note that this last one is phrased as a statement of fact, and not as an imperative given to the government. That is to say, "North Korea's government is derived from the public", and _not_ "North Korea's government should be derived from the public".

I will concede that these snippets are taken from the 1972 constitution, which has since been revised a couple of times. However, given the addition of an article declaring Kim Jong-Il to be Supreme Leader in the 2009 constitution, I suspect what the North Korean government is doing is entirely legal, unless you are suggesting that they are somehow bound by (e.g.) the U.S. constitution.

EDIT:

Ooh, here's another good one:

Article 11. The Democratic People’s Republic of Korea shall conduct all activities under the leadership of the Workers’ Party of Korea.

So, it would actually be illegal for the current government to not be the current government. They are legally obligated by their constitution to maintain the dictatorship.

I can't argue with that, it seems that they actually made themselves a constitution that makes their current government legal.

Is the down vote disagreeing or my anti-religion snideness? If it's the former, quoting from http://laws.justice.gc.ca/en/charter/1.html

    PART I OF THE CONSTITUTION ACT, 1982(80)

    Assented to March 29th, 1982

    PART I
    CANADIAN CHARTER OF RIGHTS AND FREEDOMS
    Whereas Canada is founded upon principles that recognize the supremacy of God and the rule of law:

    ...