Tory peer Ruth Davidson has hit out at John Swinney’s plan to work with Sinn Fein in his bid to break up the UK, describing it as ‘beyond the pale’.

The former Scottish Conservative leader said the SNP’s pledge showed that it ‘doesn’t take long for the mask to slip’.

Joining Tory leader Russell Findlay and local candidate Annie Wells in Rutherglen, near Glasgow, yesterday, Baroness Davidson said that she was ‘disappointed’ to hear the First Minister say he would work with Sinn Fein.

She said: ‘I’ve known John Swinney for a long time and I never thought he’d stoop so low.

‘He tries to portray himself as a sort of everyman-cum-bank manager but it doesn’t take long for the mask to slip, does it?

‘To say that you would work with people like Sinn Fein to break up the United Kingdom…obviously [Sinn Fein] are the political wing of the IRA which caused destruction, violence, all of that. It’s just beyond the pale.’

Earlier this week, Mr Swinney revealed plans to work with Sinn Fein, which has historic links to IRA terrorism, and Welsh nationalists Plaid Cymru, to ‘change the dynamics’ of the UK ‘irreversibly’.

Polls suggest that next month’s election will see separatist parties win in Scotland and Wales, with Sinn Fein already in power.

 Following his comments, Michelle O’Neill, the Sinn Fein First Minister of Northern Ireland, said: ‘There is a crack in terms of the Union and the disunited kingdom is very much on show. We could, in the next number of weeks, have a very historic and seismic moment.’

Sinn Fein MP John Finucane also latched on to Mr Swinney’s comments. Writing on social media, he said: ‘Sinn Fein will work with all those parties who share the desire and pursuit of independence, including those in Scotland and Wales who want to break the shackles of Westminster rule.’

However, Ms Davidson said that an SNP majority in the Holyrood elections isn’t a certainty, despite several polls indicating that the Nationalists could end up with one. YouGov predicted earlier this month that the SNP could be on course for 67 MSPs, giving them a five seat majority, with Reform securing 20 MSPs, Labour getting 17 and the Tories just seven.

Another poll from Survation, published last week, predicted the SNP could fall short of a majority, securing 35 per cent of votes in the constituency and 29 per cent in the regional list. Most polls show both Labour and the Tories returning fewer MSPs than in 2021.

Ms Davidson said: ‘It’s really important for Mail on Sunday readers to know this isn’t an inevitability. There is a way to stop him, and that is using your peach ballot to vote for the Scottish Conservatives, because John Swinney can’t do anything without a majority.

‘The fact that he arrogantly thinks he’s going to get one and that he can work with these people... let’s not give him the satisfaction. Let’s show that we can stop him.’

Ms Davidson, who now hosts a podcast alongside her role in the House of Lords, said not only were the SNP a threat to the Union, but that Nigel Farage’s Reform UK couldn’t be trusted either.

She added: ‘The difficulty I have with what Reform have been saying [about the constitution] is they don’t seem to be able to stick to a line on this one.

‘They’re happy to field candidates that don’t support the United Kingdom. They’re happy to be equivocal about what sort of trade-offs they’d give to the SNP, and I’m not sure the Scottish public are in a position where that’s good enough.

‘When you’ve got John Swinney saying that he’s going to work with Plaid Cymru, he’s going to work with even Sinn Fein to try and break up the United Kingdom…he’ll work with anyone.

‘It needs people that really believe in the United Kingdom and believe in the decision that the people of Scotland made in 2014.

‘This was our decision. We chose to stay. We have to honour that.’