Political system of UK
The United Kingdom of Great Britain and Northern Ireland is a constitutional monarchy. That is, it is a country governed by a king or queen who accepts the advice of a parliament. Second, it is a unitary state, as it unites four different countries. Finally, it is also a parliamentary democracy. That is, it is a country whose government is controlled by a parliament elected by the people. In other words, the basic system is not so different from anywhere else in Europe. The highest positions in the government are filled by members of the directly elected parliament. In Britain, as in many European countries, the official head of state, whether a monarch or a president, has little real power.
Britain is almost alone among modern states in that it does not have a constitution. Of course, there are rules, regulations, principles and procedures for the running of the country, but there is no single written document which can be appealed to as the highest law of the land.