Former Taoiseach John Bruton has said Britain should change its mind on Brexit and stay in the European Union.
Speaking to RTÉ, Mr Bruton said the choice was between a hard Brexit and no Brexit. Anything in between, he said, would not work.
On the EU border between Northern Ireland and the Republic, Mr Bruton said minimal barriers could result in law enforcement from one side of the border being able to do operations on the other side. This would be similar to the current arrangement between Norway and Sweden.
Mr Bruton said he was glad to see the border top of the agenda for negotiations but warned that trade was also of key importance. Major questions include whether tariffs will be applied to goods and how high they will be.
He also said it remains to be seen if Britain will continue with the Common Agricultural Policy and the European Arrest Warrant.
The former Taoiseach said people had voted to leave the EU on the basis of promises that were invalid. He said negotiations would be more complex than anyone had envisaged.