Tony Blair once suggested that nationalists could support England in the World Cup after the Republic of Ireland was knocked out, according to reports on a 2002 meeting.
The former prime minister and architect of the Good Friday Agreement was said to be “crestfallen” after the gaffe, which is detailed in newly unsealed documents from the Irish National Archives in Dublin.
Ireland were knocked out in the second round of the World Cup, jointly hosted by Japan and South Korea, following a penalty shootout with Spain on June 16.
The next day, Mr Blair attended a meeting with SDLP leader Mark Durkan and NSecretary of State John Reid to discuss policing and a recent Criminal Justice Bill.
Other SDLP representatives at the meeting later relayed to Irish officials that the prime minister appeared disengaged and tired.
The briefing document states that he was undoubtedly somewhat distracted by the Black Rod affair, which involved a row with the press over claims that No 10 tried to push for a more prominent role for the Prime Minister in the Queen Mother’s lying in state and funeral.
He did not seem to have an appetite for discussing Northern Ireland, the briefing note says, and while listening would refer answers to Mr Reid - who was “convivial and charming in a slightly desperate kind of way”.
On entering the room, Mr Blair is said to have commiserated on Ireland’s defeat and “offered, apparently genuinely, that the SDLP were now supporting England.”
The revelation, revealed in a footnote, continues: “Blair was a bit crest fallen to hear Durkan express himself in a very non-committal manner on the matter of England’s likely fortunes”.
The awkward moment could have been avoided altogether had the meeting occurred just five days later, given that England were knocked out in their quarter-final with eventual champions Brazil on June 21.
Ireland’s 2002 World Cup campaign was otherwise marred by controversy, after captain Roy Keane pulled out in protest following a public row with manager Mick McCarthy over a range of issues including training conditions in Saipan.
The newly released documents also contained details on another moment in which the prime minister was left red-faced.
Earlier the same year, Mr Blair admitted to Taoiseach Bertie Ahern that he was “stunned” after Sinn Féin was offered offices in Westminster for their abstentionist MPs.
Sinn Féin MPs do not take their seats in Westminster.
The move was met with backlash from Conservatives and Unionists, who said it carried security issues.
Nine Labour backbenchers also voted against the British government’s motion.
Mr Blair told Mr Ahern he was stunned by the negative reaction, with the Irish record of the meeting showing the prime minister remarking that he had been naive.
The minutes of the meeting state: “Sinn Féin in return must acknowledge that they had some sense of responsibility.
“There is a feeling that after their electoral successes, they need to play by ‘our rules’.”