This diploma thesis deals with the issue of presidential policy in the case of the Prime Minister of the United Kingdom of Great Britain and Northern Ireland. The The diploma thesis focuses on how the British Prime Minister's relations with other cabinet members have changed in the context of European integration. We explore the first year of Theresa May's first cabinet. The work takes into account the historical development and the moments that are relevant to the topic. It also has done an excursion to the history of Eurointegration in relation to Great Britain or those events that could have determined the current developments that resulted in the vote on Brexit and Theresa May taking the office of the Prime Minister of Great Britain.