four home nations - England, Scotland, Wales and Northern Ireland - entered an agreement in February 1993 which set down the
criteria for determining the international eligibility of players holding a
player is eligible to play for one of the home countries if:
it is the country of his birth.
it is the country of birth of his natural mother or father.
it is the country of birth of one of his natural grandmothers or grandfathers.
player who holds a current British passport but whose natural parents and
natural grandparents were born outside the United Kingdom is eligible to play
for the home country of his choice.