Margaret Thatcher secretly voiced fears of an Asian rising in Britain if Irish nationalists were allowed to express their identity in Northern Ireland, newly-declassified government files reveal.
In a crucial peace-building summit between the then prime minister and Ireland's premier Garret FitzGerald in 1984, Mrs Thatcher said she could not understand why Catholics in the region were looking for certain rights.
At the November 19 talks in Chequers, the Tory leader said there were minorities all over Europe who were not making the sort of claims nationalists were for reforms in policing, justice, equality and power-sharing.
During their exchanges, described by those at the top-level meeting as rapid and vigorous, Mrs Thatcher fretted about the wider consequences of addressing Catholic alienation in relation to ethnic minorities in Britain.
She said: "… if these things were done, the next question would be what comes next? Were the Sikhs in Southall to be allowed to fly their own flag?"
Southall is a west London suburb with a large Asian community which was the scene of a notorious race riot just three years earlier.
In files marked "secret", and just released in Dublin's National Archives, an official note of the two-hour Chequers summit reveals Mrs Thatcher's "incomprehension" as to what exactly Irish nationalists wanted.
Mr FitzGerald, then leader of the Fine Gael party, explained that the minority felt Irish and part of the majority of the island of Ireland "from which they had been cut off by an arbitrary act".
The British had drawn a line around the six counties, creating a Protestant majority, cutting off the minority from the nation and people were "set against each other within a narrow space," he said.
The Taoiseach added there was "hard evidence" of bias in the justice, security and policing systems in Northern Ireland while the guns of the British Army's controversial Ulster Defence Regiment were being used to "bully" Catholics.
He warned Mrs Thatcher that she needed to deal with the alienation of northern nationalists.
"They cannot fly the flag of their own nation in their own country" he said.
But Mrs Thatcher insisted she could not understand why a minority would seek "particular prerogatives as of right".
Turning to Europe, she said Macedonians, Croats, Serbs and Sudetan Germans were minorities who had no special rights in their countries.
But Mr FitzGerald rejected the comparisons.
The Taoiseach asked his British counterpart where else in the world could one sixth of the population say they had relatives imprisoned.
The death toll at that time was the equivalent of 100,000 in the UK, he said.
Mrs Thatcher mistakenly said there had been 2,500 deaths in the security forces, with Mr Fitzgerald correcting her that the majority were civilians, most of them Catholics.