Former Taoiseach Bertie Ahern has hit out at Theresa May's handling of Brexit from start to finish.
Mr Ahern said the suggestions made by Mrs May to EU leaders in Brussels this week were "absolutely crazy" and he detailed a litany of "terrible mistakes" she has made during her tenure as British prime minister.
Mr Ahern also warned that if the backstop goes there would be a return to a hard border, which he said cannot happen.
Speaking on RTE radio this morning, Mr Ahern said: "I have some sympathy for Theresa May but I have to say it's only on a personal level, she tried to make a speech the other day and she was exactly 50 seconds into it when they started heckling her, her speech was only nine minutes so I thought it was bad manners."
However, Mr Ahern dismissed Mrs May suggestion, which was rejected by the EU Council, that the aspirational future relationship document be placed into the withdrawal agreement.
"To be polite about it she didn't make a lot of sense."
Hitting out at other decisions made by the prime minister, he said: "She created the red lines without consulting her cabinet or even her senior cabinet ministers, the Lancaster House speech she made in January of 2017 brought the Customs Union into it for the first time which I think was a terrible mistake.
"She called a general election after going for a walk in the hills over the Easter Holidays.
He said the argument of Brexiters that the backstop can be softened is not an option.
"The backstop has to remain in place if we want a frictionless border, it's not something that we threw in just to have a word in the game.
"We can't give an inch on it."