What is the problem with Ireland?
They are called Northern Ireland and the Republic of Ireland, not Southern. To keep it as short as possible, basically, the whole Island used to be part of the UK. Ireland became a free state in 1922, but the following day the six counties (now Northern Ireland) chose to opt out due to the Unionist majority (Which was due to the plantation of Ulster which has been mentioned above) Northern Ireland will remain part of the UK until a majority vote otherwise.
