Oliver Cromwell
Oliver Cromwell, Lord Protector- and he didn't rule Scotland.
The United Kingdom of Great Britain and Northern Ireland has a Queen - Her Majesty Queen Elizabeth II - and not a king. For other monarchies around the world, see the related question below.
A queen can rule a kingdom. Queen Elizabeth II is the ruler of the United Kingdom. The word kingdom is taken to mean an area ruled by a monarch (rather than only a king).
A Queen Regnant is the monarch, and an outright ruler in her own right; a Queen Consort is only a queen by virtue of being married to the King, who is the monarch. The same thing for the King.
Don't be silly! We have no king, only the Queen!
There is no king malinda. There is only queen malinda. She was the ruler of Ireland from 1678 to 1689. Then she died when Marcus Tuvalu snuck into her castle and shot Queen Malinda.
In the UK, a Queen can be both a female ruler, or the wife of a male ruler. On the other hand, King only describes a male ruler - the husband of a ruling female is known as a Prince Consort. So, Catherine Middleton would become a Queen if William takes the throne. However she'll be a Queen Consort in this case, different to Elizabeth II, a Queen Regnant.
The previous sovereign only had daughters, so one of then succeeded him.
Silly question really. If we are talking Great Britain, there have been only four King William's.
When there is only one ruler, it is typically referred to as a monarchy if the ruler is a king or queen, or as a dictatorship if the ruler has absolute power without constitutional limitations. In both cases, the authority is centralized in a single individual, who often has significant control over the state and its governance.
No Great Britain is not an octarchy because it is ruled by a king and queen. An octarchy has t be ruled by 8 rulers or else it is not an octarchy. Hope this helps!
Assuming you mean the monarchs in Britain only, there were actually three: Queen Victoria, King Edward VII, and King George V.