The First Minister will today unveil plans to "forge a way forward" without the UK Government’s approval as she seeks to hold another vote in October next year.
It came as Scottish ministers were accused of “frittering away money on a reckless fantasy” after it emerged the number of civil servants working on their independence plans has risen again.
A Freedom of Information request by pro-UK campaign group Scotland in Union found staffing resources have increased from 11 at the start of the year to 20.
Ms Sturgeon wants to hold another referendum next year, but the UK Government is unlikely to agree to this.
The First Minister previously promised a “significant update” on a route forward without the relevant powers being granted by Westminster for a repeat of the 2014 vote.
Ahead of a statement in the Scottish Parliament, she said: “The people of Scotland have elected a Parliament committed to giving them a choice on independence, and so that democratic will must be respected.
“In Scotland, it is the people who are and have always been sovereign – and it is the people’s will which must prevail.
“That may be an inconvenient truth for our political opponents, but it is a simple and unavoidable truth nonetheless.
“Continued attempts to block that democratic will only weaken the UK Government’s standing, here and internationally.
“Bluntly, the UK Government is in no position to lecture any other country about the need to respect democratic norms if it is intent on trying to thwart democracy at home.
“And, because we live in a democracy where election results still matter, continued efforts to thwart the will of the people must – and will – fail.
“The UK is either a partnership of consent or it is not a partnership worthy of the name. Westminster rule over Scotland cannot be based on anything other than a consented, voluntary partnership.”
Alastair Cameron, director of Scotland in Union, said the increasing number of civil servants working on an independence prospectus “demonstrates a totally unacceptable waste of taxpayers’ money by the SNP”.
He said: “These are senior, highly-paid and expert civil servants who could be devoting their time to pressing matters such as reducing NHS waiting times or closing the attainment gap in our schools.
“Instead, they have been tasked by SNP ministers with working on a blueprint to divide the people of Scotland.
“The majority of people in Scotland don’t want to leave the UK, and voters are strongly opposed to another referendum next year.”
Scottish Conservative MSP Donald Cameron said: “Right now, ministers should be prioritising the global cost-of-living crisis, fixing our NHS and rebuilding our economy from the pandemic.
“It is disgraceful that Nicola Sturgeon would put all that on the backburner to push for another unwanted – possibly even illegal – referendum.”
Scottish Liberal Democrat leader Alex Cole-Hamilton said: “Nicola Sturgeon’s desire to break up the UK is out of touch, obsessive and desperate.”