DOWNING Street has suggested that Nicola Sturgeon’s desire to push for a separate deal for Scotland on Brexit could undermine Theresa May’s attempt to get the best outcome for the United Kingdom through trying to adopt a unified UKwide approach.

Just 24 hours before the First Minister sets out her EU options paper, entitled "Scotland's Place in Europe", the Prime Minister’s spokesman was asked if Mrs May would rule out devolving more powers to Scotland to allow it to stay within the European single market.

He replied: “We are committed as we leave the EU to getting a deal that works for the UK as a whole. That means a deal that works for Scotland as well. We have been very clear we want a deal that allows British firms to have maximum access and freedom to operate within and with the single market.”

He then said: “We are of the opinion we will get the best deal for the UK if the UK is unified in its response; that will maximise the impact of our negotiations.”

Asked what the implications would be for cross-border trade if Scotland stayed within the single market, he replied: “The referendum decision was taken by the UK as a whole and the UK as a whole will leave the EU. So we are not anticipating the scenario played out because we will be leaving the EU as a whole.”

When pressed on his comment about a unified approach maximising the chances of getting the best deal for Britain and whether or not the FM might undermine that by pressing for a separate Scottish deal, the spokesman said: “What I meant was that is our position; I was not conjecturing that Scotland wouldn’t.

“We are going to leave the UK as a whole. The referendum decision was taken by the UK as a whole and we will leave the EU as a whole. We have been very clear we are going to get the best deal as we enter these negotiations for the UK; that’s one that works for all parts of the UK. As part of that we will continue to work closely with the Scottish Government.”

It is thought the SNP administration’s paper will make clear the best option for the whole UK is for it to stay within the single market, although this would involve free movement of people, which the PM has ruled out. Failing that, the next best option is for Scotland to remain within the single market as the rest of the UK leaves it.

Michael Russell, the SNP minister involved in the intergovernmental discussions, has talked up the Norway option, which means the Scandinavian country abides by the so-called “four freedoms” of the single market – on the free movement of people, goods, services and capital across borders - but does not give it any power in the decision-making process. Such an option would fail one of Ms Sturgeon’s five key tests to protect Scotland’s interests, which she set out in the summer following the referendum result.

On a recent visit to Scotland, Philip Hammond, the Chancellor, dismissed as “not realistic” the prospect of a Scotland-only deal, his colleague David Mundell, the Scottish Secretary, also categorically ruled out a separate deal but conceded it might be possible for Scotland to have a “differentiated option” within the UK Brexit strategy. Meantime, Robert Goodwill, the Immigration minister, has also dismissed the idea of Holyrood have more powers over immigration.

In January, there will be a Joint Ministerial Committee meeting between the two governments and the other devolved administrations to discuss Ms Sturgeon's options paper. Towards the end of the month, there will be the final key plenary JMC chaired by the PM when it is expected that the FM will make clear whether or not the UK's strategy on Brexit is acceptable or not to the Scottish Government. Given David Davis, the Brexit Secretary, has suggested the full UK Government strategy will not be published before February, then it is possible another JMC session could take place, involving St Sturgeon, before Mrs May seeks finally to trigger Article 50 by the end of March.

At the weekend, Alex Salmond, the former First Minister claimed the Yes side would win a future Scottish independence referendum if the UK Government was determined to "sever" Scotland's European links.

The MP for Gordon said any such move by the UK Government would see people, who were previously sceptical about independence, switch to supporting the campaign for Scotland to leave the UK.

He said: "The last time, when I was First Minister and embarked on this process and support for independence was 28 per cent, after two years we ended up at 45 per cent.

"So I don't think Nicola Sturgeon would have any compunction about calling an independence referendum with support in the mid-40s," added Mr Salmond.