A SENIOR Nationalist MSP has been accused of parting company with reality after claiming there is no such thing as the UK single market.

Joan McAlpine, convener of Holyrood’s European Committee, stunned an event at the Scottish Parliament’s Festival of Politics by saying it was “a bit of a nonsense”.

The single market refers to the border-free movement of goods, capital, people and services inside the UK - an arrangement Scottish independence might end, Unionists warn.

However Ms McAlpine, who was chairing a discussion about Brexit, appeared to think devolution meant the UK had already lost its frictionless economy.

READ MORE: Joan McAlpine letter - Questioning the term 'UK Single Market' was stirring up debate

The South of Scotland MSP was immediately corrected by two of her panelists.

Ms McAlpine said: “This talk of the UK single market, it’s a bit of a nonsense when you think that under the devolved settlement we already have different approaches to things.

“Health, for example, and lots of other areas as well where we take a different approach.

“So we don’t really have a UK single market.”

Professor Nicola McEwen, Associate Director of the Centre for Constitutional Change at Edinburgh University, promptly told her: “Yes, we do.”

Alan Page, Professor of Public Law at the University of Dundee, then explained: “Buying and selling goods, moving job, capital - all of these things move freely within the United Kingdom to the extent that we don’t even think about it.

“We live in an economic and monetary union. We do have, no question, a single market in which goods, people, capital move freely within the UK.”

Last year Ms McAlpine wrote the foreword to a paper commissioned by her own committee which referred to the UK single market.

It said: "The devolution settlement, like the European Union, is based on a ‘single market’ in goods, persons, services and capital."

A spokesman for the Scottish Tories said: “It appears Joan McAlpine has decided to temporarily leave the reality-based community. Of course we have a UK market - just ask anyone who has popped across the border from Carlisle to Gretna to do some shopping.

“Given Ms McAlpine is a South of Scotland MSP, you’d think she’d be the first to understand this. It’s therefore extremely odd she doesn’t.”

The UK single market is key to the main Brexit legislation and the SNP’s claim that it is a Westminster “power grab”.

The EU (Withdrawal) Bill, as drafted, would see all powers repatriated from the EU at Brexit go to Westminster, even those in devolved areas such as fishing and farming.

The SNP says this breaches the fundamental principle of the devolution settlement, that powers not specifically reserved to Westminster belong at Holyrood by default.

The UK government says some powers will be forwarded to the devolved legislatures, but others must stay in UK-wide “common frameworks” to preserve the UK single market.

The goal is to avoid the different legislatures creating internal barriers to trade, for example by Holyrood insisting on different animal feed standards to England.

The UK and SNP governments are currently discussing which repatriated devolved powers should go to Holyrood and when, and which go into common frameworks.

The “Brexit - Where Now?” event also heard the reluctance to halt Brexit had created a “huge hole” in Scottish politics, as the wishes of most voters were being overruled.

Dr Kirsty Hughes, director of the Scottish Centre on European Relations, said there was a “democratic gap” and predicted either hard Brexit, no deal or no Brexit, but not a soft Brexit.

She said: “The complete political and economic crisis we would get as we plunge convincingly towards no deal is probably our best chance of actually forcing Labour to a shift, forcing the SNP to speak out and turning this around."