Nicola Sturgeon has launched her bid to become the new leader of the SNP and Scotland's first female first minister with an immediate warning to the Westminster parties that they will face an angry backlash if they fail to keep promises made on more powers for Holyrood.

In the final days of the independence referendum campaign, the Conservatives, Labour and Liberal Democrats pledged significant further devolution in the event of a No vote.

With Scotland voting to stay in the United Kingdom - a result which prompted Alex Salmond to announce his intention to resign as both SNP leader and First Minister - Ms Sturgeon demanded that those promises must be kept.

She said she would be a "willing partner for progress" in talks about transferring responsibility for more areas to the Scottish Parliament.

She declared: "If I am elected to lead, I pledge today that the SNP and the Scottish Government will be full, active, genuine and constructive participants in that process of change, wherever it happens - in Holyrood, in meeting rooms and, most importantly of all, in discussions across Scotland.

"There will be no sitting on the sidelines. But let me be equally clear what I believe Scotland expects of that process in return."

She said the deal on more powers must be one "that maximises devolution in substance not just in rhetoric", adding: "That is what I believe the majority of people of this country now want."

Ms Sturgeon, who is stepping down as SNP deputy leader to run for the party's top job, said the pro-UK parties had made a "clear and unmistakable" pledge that the package for Scotland would be "something near to federalism".

She stated: "Well, let me say this to Westminster on behalf of Scotland - it had better be.

"If the UK parties move forward in that spirit, they will have, in me, a willing partner for progress.

"If not, they will pay a heavy political price - not because I say so but because the people of Scotland will make it so."

Ms Sturgeon paid tribute to Mr Salmond, who has led the SNP for a total of 20 years and is now Scotland's longest-serving first minister after more than seven years in the job.

"Alex Salmond transformed the SNP and, as First Minister, he has made Scotland a better place," she said.

"He also helped to make me the person and politician I am today. The personal debt I owe him is immeasurable.

"I will be proud - if given the opportunity - to build on his remarkable legacy."

Ms Sturgeon, who has been deputy leader of the SNP for the last 10 years and Deputy First Minister since 2007, said: "To be the first minister of my country, especially at this exciting and optimistic time, would be both a great honour - without doubt, the greatest honour - and an immense responsibility.

"I am putting myself forward for two simple reasons: I want to serve my party and my country. And I believe I am the best person for the job."

She is now in line to become Scotland's first female first minister, as well as the first woman to lead the SNP.

She said: "I also hope my candidacy, should it succeed, will send a strong message to every girl and young woman in Scotland: no matter your background or what you want to achieve in life, in Scotland in 2014 there is no glass ceiling on ambition."

While Ms Sturgeon paid tribute to Mr Salmond, she was also keen to state: "I will be my own person and set my own course.

"At risk of stating the obvious, I am not Alex Salmond. His are big boots to fill, but if given the opportunity to lead, I will wear my own shoes - and they will certainly have higher heels!"

Although she said the case for Holyrood having more powers was now "urgent and irresistible", Ms Sturgeon stressed that if she becomes first minister, "my responsibility will also be to use those powers we already have to make life better, now, for those we serve".

She pledged: "Any Government I lead will always take seriously its responsibility to make the very best of the limited powers at Holyrood, whilst also arguing Scotland's case for greater authority and the tools capable of transforming our nation. Those positions are not mutually exclusive - rather, they are the essence of responsible national leadership.

"My guiding ethos is a social democratic one and that will be the ethos of any government I lead. I believe that a strong, sustainable economy with a vibrant business community, and a fair society with strong public services are two sides of the same coin. We cannot succeed and flourish as a society without advancing both."

She added: "If the SNP chooses me as its leader and the Scottish Parliament then elects me as first minister of our country, these priorities of democracy and equality will be at the heart of all that I do.

"It is hard to overstate the sense of opportunity that I feel as I contemplate what will be - if my party and Parliament so decides - the biggest challenge and greatest privilege of my life. If elected, I will bring to this job seven years of experience in government but also a real sense of new and different possibilities. I can't wait to get to work."

Ms Sturgeon dismissed any suggestion that there could be another route to independence for Scotland other than a referendum.

She refused to say if the manifesto she would put forward for the 2016 Holyrood elections would include a commitment to holding such a vote.

But she said if the pro-UK parties made good on their pledge of substantial devolution, the country would "travel a significant distance" towards self-governance.

"I'm not preparing for another referendum, we've just had a referendum," she said.

"But one thing that is very important for politicians to understand, myself included, is the question of if and when there will be another referendum will be dictated by circumstances and the mood of the public."

Ms Sturgeon stressed: "Scotland will only become independent if the people of Scotland vote for independence in a referendum. There is no short cut to independence.

"But if the UK parties honour the promise of the last few days of the referendum campaign, we will travel a significant distance to independence.

"If certain things happen, if the UK Government reneges on the commitments made about more powers, if a European referendum takes, or threatens to take, Scotland out of the European Union, you may well have circumstances in which the people of Scotland will be demanding the right to choose a different future for Scotland."

Whatever powers Scotland has, she said if she becomes first minster she would use these "wisely" and "creatively".

Ms Sturgeon vowed: "If I am first minister, my responsibility every single day I am in that job will be to govern well, wisely, creatively and innovatively with the powers I have at that time."

She declared her bid for the leadership of the SNP on the first day that nominations for the post opened.

While she is the overwhelming favourite for the position, she said: "I would welcome a contest, I would absolutely relish the prospect of a contest, but that is not within my gift."

Ms Sturgeon became deputy leader of the SNP in 2004 when she stood on a "dream ticket" with Mr Salmond.

But she said today she would not be endorsing any candidate for deputy, insisting: "There will be no joint ticket. I think it is important the party gets a free choice."

Meanwhile, more than 32,000 people have joined the SNP in the wake of the referendum. Membership of the party now stands at more than 57,000, a huge surge from the 25,642 recorded last Thursday.

SNP business convener Derek Mackay said the influx of new members "shows no signs of slowing down".