::::::::::: In my view the position of the UK Government should come before that of Irish nationalists, and quoting the web site of Sinn Fein - until fairly recently the political wing of a terrorist group - is completely unacceptable to me, as well as unnecessary. I would propose to tweak the text as follows: 

 "A country is usually considered to be a sovereign state (or, more broadly, the term is indicative of the autonomous nature of a territory's government: see for example, The Oxford English Dictionary definition of "country"). The United Kingdom, as a sovereign state, is a country. However, by convention England, Scotland and Wales have historically always been referred to as countries regardless of their precise constitutional arrangements. The British government (as in the Prime Minister's website) and other sources, often refer to Northern Ireland as a "country" to reflect its existence as a parallel entity to England, Scotland and Wales. For further information see Country, Terminology of the British Isles and Constituent country#United Kingdom." For this reason, the British Prime Minister's website has, in the past, used the phrase "countries within a country" to describe the United Kingdom. With regard to Northern Ireland, the descriptive of "country" "can be controversial, with the choice often revealing one's political preferences" and terms such as "region" or "province" are preferred. (J. Whyte and G. FitzGerald, 1991, Interpreting Northern Ireland, Oxford University Press: Oxford).