Nicola Sturgeon will today use her visit to Dublin to press for the entire UK to retain membership of the EU single market after a former Irish Prime Minister dismissed her claim Scotland alone could stay in.

The First Minister will tell a business breakfast attended by around 130 chief executives that the single market is good for the entire British Isles and the Irish Government has a “strong ally” in Scotland to help secure this goal.

She received some encouragement yesterday on the first day of her two-day trip yesterday when Charlie Flanagan, the Irish Foreign Affairs Minister, pledged to be “helpful” to Scotland during the Brexit negotiations.

But John Bruton, the former Irish Prime Minister, described as “nearly impossible” Ms Sturgeon’s proposal for Scotland to remain in the EU single market if the rest of the UK leaves.

Mr Bruton, who was Ireland’s Taoiseach between 1994 and 1997, said he did not see how it was possible to have two sets of trading rules on the British mainland.

His scepticism echoed that of Carwyn Jones, the Welsh First Minister, who said the proposal was unworkable and would require customs posts at the border between England and Scotland.