Person who is responsible for the political guests in the kingdom?

There are a number of different officials who might be responsible for handling different aspects of a visit to a monarch, but I believe you are referring to the court Master of Ceremonies.

In England (and later Britain and the UK), the position was Master of the Ceremonies, assisted by an Assistant Master of Ceremonies and by a Marshall of Ceremonies, responsible for the reception of visitors to the court; put more formally,

This Office was instituted by K. James I. for the more solemn and honourable reception of Ambassadors and Strangers of Quality, whom he introduces into the Presence.

Wikipedia has a list of office-holders from 1603.

I would caution, however, that a master of ceremonies would not be understood to be a court officer in the present day. For one thing, in 1920 the position was abolished and replaced with Marshal of the Diplomatic Corps, who administers relations between the sovereign and the heads of foreign diplomatic missions to the UK. For another, the term is now used for very different roles. An M.C. (or emcee) at a staged event is the main host and toastmaster, i.e. the person who opens and closes the event, introduces speakers or acts, and entertains the audience during interludes. And in hip-hop culture, MC usually refers to a rap performer.

Sometimes this person is called a protocol officer.

A WiseGeek webpage explains:

A protocol officer is someone employed by a government agency or major corporation in order to facilitate meetings, ensure proper etiquette for official engagements, and streamline interactions with dignitaries and other important people. The job typically involves some elements of event planning, but focuses more on personnel issues. A protocol officer’s main job is to guide leaders, be they elected officials or corporate executives, away from etiquette or cultural mistakes .. In most places, protocol officers are best known for their work in top-level government institutions. Presidents, Prime Ministers, Senators and foreign diplomats are among those who hire protocol officers to help them forge important relationships without making embarrassing blunders.

The highest-ranking protocol officer for a company or nation may be called the chief of protocol:

The Chief of Protocol of Canada is considered the most senior protocol officer for high-level international visits to Canada and outgoing state, official and working visits, as well as for overall issues relating to the entitlements and special status granted to the foreign diplomatic community in Canada, which includes a number of international organizations.
_{Source: About Angela J. Bogdan, Chief of Protocol of Canada}