The SNP plans to introduce a bill that would allow Scotland to decide on independence without the UK government’s approval.
The party is pushing for Holyrood to hold its own referendum on independence to “unlock Westminster’s denial of democracy”.
It wants to amend the Scotland Act 1998, which details what Holyrood can and cannot legislate on.
This includes “the Union of the Kingdoms of Scotland and England” and “the parliament of the United Kingdom”.
The SNP pledged to continue its fight for independence last month after the Supreme Court ruled the Scottish Parliament cannot hold a second referendum without Westminster approval.
Stephen Flynn, who has taken over from Ian Blackford as SNP leader at Westminster, claimed Scottish people “have already voted for a referendum and now is the time for one”.
“That is a democratic reality that politicians at Westminster must wake up to,” he said.
A new poll has suggested Scottish voters back independence over remaining in the UK.
The YouGov poll, reported by the Times, found 47% would favour independence, while 42% support staying in the union.
Mr Flynn said it is the “fourth poll in a row” that has shown the majority of Scotland support independence.
“But with both the Tories and Labour joined at the hip in blocking democracy, it cannot be business as usual at Westminster,” he added.
After the Supreme Court ruling, SNP leader Nicola Sturgeon said the next general election will act as a “de facto referendum” – with more than 50% of the vote for pro-independence parties needed for a mandate.
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Next election is ‘de-facto indyref2’ But her critics have warned this would have no legal validity, and the YouGov survey also suggested voters could be unsure about that plan.
Some 52% said they do not think a pro-independence vote majority would constitute a mandate for a referendum.
Plans for the new bill come as Scottish government ministers face accusations of “vanity” independence spending before the upcoming budget statement on Thursday.
The Scottish Tories, including the party’s finance and economy spokeswoman Liz Smith, have urged the SNP to support households and key public services amid rising costs.
Ms Smith said the SNP is focused on its “independence obsession” and “sitting on money that could help hard-pressed families and businesses now”.
She added: “It should immediately divert its vanity spending on a referendum that the courts have ruled out and abandon reckless plans for a costly, centralised National Care Service that everyone else can see is a bad idea.”