n): A discrete region inhabited by roughly one-thousandth of the world population.
THE Greco-Roman geographer Ptolemy (Alexandria 100-170) referred to the island of England, Scotland and Wales as "Great Britain" and the island of the Republic of Ireland and Northern Ireland as "Little Britain".
With a population of 6.4 million, "Little Britain" qualifies as a millisphere (4.6 million in the Republic, and 1.8 million in Northern Ireland).
The United Kingdom's proposed "Brexit" from the European Union has put the focus back on the border between the Republic and the UK. Contentious and heavily guarded during the latter half of the 20th century, today this "open" border is differentiated only by the colour of the verge markings and the euro/pound currencies.
Nominally claimed by the Normans when they invaded Great Britain in 1066, "Little Britain" wasn't occupied until Tudor times. "The troubles" in Northern Ireland have their root cause in mass immigration from Great Britain and the introduction of Protestant English rule, marginalising the native Irish Catholics.
During the 1845-1852 Irish potato famine, one million people died, another one million emigrated and the population dropped by one-third.
The population of "Little Britain" has yet to return to its pre-famine peak.
The Irish uprising of 1916 was brutally put down by London. Fifteen Nationalist leaders were executed and thousands imprisoned, turning many Irish against the United Kingdom and, in 1949, the Republic of Ireland won its independence.
Conflict continued in Northern Ireland between Catholics and Protestants, claiming 3600 lives before the Good Friday Agreement of 1998 which included self-government for Northern Ireland jointly headed by a Unionist First Minister and a Nationalist deputy First Minister.
More importantly, in 1973 the Republic of Ireland and the United Kingdom joined the European Union and "Little Britain" changed from an agricultural society to a high-tech "Celtic Tiger" economy.
In 1999, the Republic adopted the euro as its currency, subsequently enjoying an annual growth rate nearing 10 per cent.
"Little Britain" now has an open border with the free movement of people, goods, services and capital.
By 2015, the Republic was the sixth most developed nation according to the United Nations human development index and all-island institutions now manage electricity, natural gas, waterways, food safety, trade, EU programmes, language, the coast, lighthouses and the marine environment.
After "Brexit", when the UK voted to leave the European Union, the all-Irish farming and food sectors were "terrified" at the prospect of a hard post-Brexit border which others saw as "an obvious target for dissident republican terrorists and a threat to the Irish peace process".
Theresa May's Conservative Party enjoys a parliamentary majority with the support of the Northern Ireland Democratic Unionist Party, and DUP leader Arlene Foster said no to a hard border.
Northern Ireland - along with London - voted to stay in the EU and 58 per cent of people in Northern Ireland want to stay in the "all-Ireland" single market and customs union after "Brexit".
The business sector called for customs clearing by computer and electronic number plate recognition, pointing out that half of all-Irish workers live in the trans-border Belfast-Dublin corridor.
South of the border, Irish Prime Minister Leo Varadkar enjoyed a surge in support on the back of the "Brexit" row when he joined the call for an open border. Irish deputy PM, Simon Coveney, added provocatively that he hoped to see a united Ireland in his lifetime, no doubt making DUP founder and hardline Protestant Ian Paisley spin in his grave.
On the other side of the Irish Channel, British Foreign Affairs Minister Boris Johnson said "Brexit" was about "taking back control of our laws, of our borders and of our cash", while English Conservative MP Bernard Jenkin added: "The Irish government is being played like a harp by the EU."
The Northern Ireland bombings and shootings didn't go away entirely after the Good Friday Agreement, and a member of an IRA splinter group was recently jailed for buying grenades on the dark net, and another was sentenced to 11 years in prison for planning to blow up Prince Charles.
In Ireland there has always been a fine line between sectarian freedom fighters and criminals, extortionists and killers.
Recent history shows that "all-Ireland" economic co-operation has helped "Little Britain" transcend centuries of religious/nationalist intolerance.