The former prime minister of Ireland, John Bruton, has said he hopes the UK revisits its decision to leave the European Union.
Mr Bruton said Brexit would "cost the UK a lot of money" and it would "solve a lot of problems" if it was reversed.
In a BBC Scotland interview, Mr Bruton suggested voters be given the chance to reconsider their decision once the terms of departure become clear.
The UK government has said the leave vote must be respected.
Downing Street has repeatedly said there will be no second referendum and that the Brexit vote means the UK will leave the European Union.
Mr Bruton was Ireland's Taoiseach or prime minister 1994-1997 and later served as the EU's ambassador to the United States.
He said: "We would prefer if the people of the United Kingdom changed their minds and decided that after all they're better off in the European Union than out of it.
"It would certainly solve a lot of problems. It would relieve a lot of difficulties for Europe. It would relieve a lot of difficulties for Ireland.
"And I think it would be better economically for the people of the United Kingdom."
He expressed concern that Brexit will require border checks to be reintroduced between Northern Ireland and the Republic, damaging the peace process.
If Brexit goes ahead, Mr Bruton said it would take longer than two years for the UK to negotiate a new trading relationship with the EU and that an "interim arrangement" would be required.
Mr Bruton also cast doubt on the possibility of Scotland staying in the European single market, if the UK as a whole leaves.
"I don't see how you can have several different markets with different sets of rules and different arbitrators in different parts of what's currently the United Kingdom.
"I just don't see how that can be done. I think it's technically, administratively and politically nearly impossible" he said.
Mr Bruton has been speaking to BBC Scotland ahead of a two day visit to Dublin by Scotland's First Minister Nicola Sturgeon.
If that is not possible she would like the UK government to seek a special deal for Scotland.
She has acknowledged this will not be easy.
The Scottish government is due to set out options next month but Ms Sturgeon has already confirmed that a Norway-style relationship is under consideration.
In Dublin, Nicola Sturgeon will undertake a series of political and business meetings before addressing the upper house of the Irish parliament on Tuesday.
She held talks with the current Irish Prime Minister Enda Kenny at the British-Irish council summit in Cardiff on Friday.
Afterwards, Ms Sturgeon said: "In the post-referendum landscape, it has become even more important that Scotland and Ireland work together to strengthen our shared economic, cultural and social ties."
Scottish government figures suggest exports to Ireland from Scotland are worth more than £1bn a year and that Irish investment in Scotland supports more than 6,000 jobs.