Bertie Ahern has claimed that a Tory Brexiteer told him he didn't even know what the Irish border was.
The former Taoiseach described Tory MP Jacob Rees-Mogg as a "strange fish" and a "lovely fella when he’s asleep".
Mr Ahern, who attended several Brexit committees in Westminster, says several UK politicians don't understand what the North-South border was.
He said: "When he’s awake, he (Ress-Mogg) definitely is a strange fish I tell you, in and out of the water.
"But the reality is he admitted to me he had no idea of what the border was.
Bertie Ahern appointed honorary professor of peace studies at Queen's University Belfast
"I think a lot of British politicians thought the border was something up around Dundalk or Newry, and that there was a gate on it.
"I mean the idea that it was 460 kilometres across the island and that you could criss cross it to farms and houses, they just didn’t know it.
"And regards to the fact that lot of these guys went to Oxford, Cambridge and Eton, they’re not very bright. This is the problem. There is nothing wrong with the backstop."
The former Fianna Fail leader was speaking at a debate on Brexit at the Women In Media Conference in Ballybunion, Co Kerry.
He told the conference how the Backstop is crucial for Ireland in the EU's negotiations with Britain.
He said: "The backstop plan is essentially a safety net. If there’s no exit deal, it will avoid a hard border in the Republic. Basically that’s all it is."
