The former Taoiseach Enda Kenny has said that he is appalled at what is happening in politics in Britain in relation to the internal dissent and lack of clarity on Brexit.
He said the upcoming negotiations are so serious that the President of the European Council should consider holding an extra meeting of the council before or after the October deadline to reach a withdrawal deal.
Mr Kenny was speaking at an event organised by the European Movement Ireland at which he was named European of the Year.
His comments come as Theresa May appeals for a show of unity from her warring MPs as she seeks to avoid a series of damaging Commons defeats on her government's centrepiece Brexit legislation.
The EU (Withdrawal) Bill returns to the Commons tomorrow with ministers seeking to overturn a raft of amendments by the House of Lords intended to keep Britain close to the EU after Brexit.
However, they face a revolt by pro-EU Tory MPs determined to retain as many of the changes as possible in the legislation.
In what is likely to be a highly charged appearance before the backbench 1922 Committee this evening, Mrs May will remind her MPs they have a duty to deliver on the referendum vote to leave the EU.
She will make the point to backbenchers that while the bill itself may be a largely technical measure, the way that they vote in the division lobbies this week will send an important signal to the country.
"The purpose of the EU Withdrawal Bill is simple - it is putting EU legislation into law to ensure a smooth and orderly transition as we leave," she is expected to tell them.
"But the message we send to the country through our votes this week is important. We must be clear that we are united as a party in our determination to deliver on the decision made by the British people.
"They want us to deliver on Brexit and build a brighter future for Britain as we take back control of our money, our laws and our borders."
Despite depending on the votes of the ten DUP MPs for her precarious Commons majority, there were signs of cautious optimism among ministers that they would get the numbers to see off the revolt.
Some pro-EU Tories were reported to be backing away amid fears Mrs May could be fatally damaged by defeat, opening the way for a hardline Brexiteer to take over at the top of the Conservative party.
However, ministers were said to be taking nothing for granted with whips continuing to talk to MPs over the weekend - conversations that were expected to continue into the week.
The government is thought to be most vulnerable on two amendments - one on the customs union and the other giving parliament a decisive say over what happens next if it rejects a final Brexit deal.