Some links to definitions:
Characteristics of a country
A country usually has its own government, administration and laws; and often a constitution, police, military, tax rules, and a population who are referred to as one another's countrymen. Together they form what Benedict Anderson has referred to as an imagined community.
Scotland, Northern Ireland and Wales fulfill those criteria.
Scotland more so than Northern Ireland, and Wales only very marginally.
And also you'll note the same article in fact cites the UK and its constituent countries as an exception to the norm in the form of having Constituent Countries, which is exactlly what we've been saying :roll:
And hopefully you will also note that the other article listed contradicts this (I like to put differing versions down to enliven debate) which lists eight criteria and asserts that the constiuent entities of the UK are not countries.
The eight criteria (which I *believe* are what the UN use) are given as:
(1) Has space or territory which has internationally recognized boundaries (boundary disputes are OK).
(2) Has people who live there on an ongoing basis.
(3) Has economic activity and an organized economy. A country regulates foreign and domestic trade and issues money.
(4) Has the power of social engineering, such as education.
(5) Has a transportation system for moving goods and people.
(6) Has a government which provides public services and police power.
(7) Has sovereignty. No other State should have power over the country's territory.
 Has external recognition. A country has been "voted into the club" by other countries.
(2) and (4) I believe apply to some or all constituent entities to varying degrees, and (3) and (6) to a degree. However, trade is regulated (nominally wrt
EU) through UK Govt.; the police are ultimately Home Office (UK Govt). (7) the sovereign state is the UK, transportation is nominally a UK-wide thing (well whats not private anyway) - (1) and , surely the internationally recognised boundaries are those of the UK, and in terms of recognition, it is the UK that is represented in international bodies, not England, Scotland, etc. This also ignores the military power which again is a UK institution.