SCOTLAND’s newest party has vowed to make another independence referendum its first priority at Holyrood, in an attempt to break the SNP’s grip on the issue.

RISE will today launch an online video and petition in order to secure a “people’s mandate” for a second referendum and put the issue to a parliamentary vote after the election.

The left-wing anti-austerity alliance says its MSPs would immediately table a motion asserting the right of the Scottish Parliament – not Westminster – to stage another referendum at a time of its choosing, and invite the SNP and other parties to support it.

With the SNP shying away from a manifesto commitment to a referendum by 2021, RISE hopes the idea will help secure votes from frustrated Yes supporters.

Former SNP deputy leader Jim Sillars, who is backing RISE on the list vote, explains the idea in the video.

The Tories said returning to the referendum issue betrayed RISE’s “desperation” for votes.

Under the Scotland Act, the power to call a constitutional referendum is reserved to Westminster, meaning Holyrood cannot hold a legally water-tight plebiscite unilaterally.

Although Holyrood ran the 2014 referendum, it did so only after Westminster temporarily devolved the required powers through a so-called Section 30 order.

RISE’s petition is designed to “arm Scotland politically” by whipping up public support for a referendum in order to make Westminster concede one.

The message will be pushed hardest in the deprived working-class areas that backed Yes two years ago, with RISE pitching independence as a way out of Tory cuts.

A RISE policy document states: “The independence movement must again wield the political power to force Westminster to surrender its legal authority to the Scottish Parliament.

“RISE can arm Scotland politically by securing that mandate. First, using a legitimate democratic base to assert the right of Scots to hold the second referendum. Second, to launch and sustain an independence campaign to increase support well beyond 45 per cent. Holyrood is the pre-eminent democratic forum of the people in Scotland. It can act so that Scotland’s political power again trumps Westminster legality.”

RISE Glasgow candidate Cat Boyd said: “Scotland needs a mandate, in this election, to have a referendum in the next parliament if and when the time is right. We need to keep the pressure on Westminster and re-assert the radical demands of the independence movement.”

Lothians candidate Colin Fox added: “In presenting our case for Indyref2, RISE will stress the independence movement and the SNP are not the same thing. The movement is more diverse than one party. We need to broaden and deepen the movement to break from Tory rule."

Formed out of the Radical Independence Campaign, Scottish Left Project and Scottish Socialist Party, RISE is standing only on the list, where MSPs can be elected with just 6 per cent of the vote.

However, with the polls suggesting the SNP could win almost every constituency, the list will be the most crowded and hardest-fought aspect of the election, with all parties jostling for positions.

RISE national organiser Jonathon Shafi said: “We need to send a strong message, rooted in activism and radical ideas, that we are not going to sit on our hands for years of intensified austerity. We cannot pile pressure on the Tories if we don't integrate a second referendum into this election with a coherent plan that links the power of the parliament with that of the people."

Tory MSP Murdo Fraser said: “The people of Scotland voted decisively to stay in the United Kingdom just 18 months ago. It shows the state of desperation in RISE at their dismal poll ratings that they’re grasping at the independence straw to win some support at the election.”