NICOLA Sturgeon, the First Minister-in-waiting, has raised the possibility of a fresh independence referendum within the next few years but, in a bid to unite Yes and No voters, pledged to work with other parties to secure more powers for Holyrood.

Speaking as she launched her bid to succeed Alex Salmond, the Deputy First Minister said there were circumstances in which people might demand a second referendum in the near future.

She warned that the UK parties would face an angry backlash if they broke their promise to deliver more powers for the Scottish Parliament.

She also said a future in/out EU ­referendum, which is backed by Prime Minister David Cameron, could justify a second independence poll if it threatened to remove Scotland from Europe as a result of the vote in England.

Ms Sturgeon refused to rule out a fresh referendum if the SNP wins a majority in the next Holyrood election in 2016. However, she stressed her immediate priority was to press for more powers for the Scottish Parliament.

Pledging to play a "full and active" role in Lord Smith of Kelvin's commission to reach cross-party ­agreement on further devolution, she said: "The fact is that those who voted Yes combined with those who voted No on the promise of substantial extra powers form a powerful majority for real and meaningful change in this country.

"It is that change that must now be defined and delivered."

Without issuing detailed demands, she called for new powers to create jobs, tackle inequality, protect public services and deliver fair social security.

However, she said it was highly unlikely she would seek to block the eventual package of measures - which will require the approval of MSPs - even if she felt it was inadequate.

She said: "I struggle to see any circumstances where I would be ­blocking more powers for the Scottish Parliament. It runs counter to everything I stand for."

At the weekend, the outgoing First Minister said there were "many routes" to independence after last week's referendum resulted in a ­decisive No vote. Mr Salmond suggested the party might return to its earlier policy of seeking a mandate by winning an election in Scotland.

Setting out her own leadership plans, Ms Sturgeon told a press conference at Glasgow Royal Concert Hall: "Scotland will only become independent if the people of Scotland vote for independence in a referendum.

"There is no short-cut to independence, I believe that very strongly."

Ms Sturgeon, who appears certain to succeed Mr Salmond when he steps down in November, praised the First Minister, insisting he had made ­Scotland a better place and pledged to build on his "remarkable legacy".

But she added: "I am not Alex Salmond. I will be my own person and set my own course. The challenges and opportunities of tomorrow require a different approach.

"They will demand the ability not just to argue a case with determination and conviction but also to reach out, to work with others and seek common cause on the issues that unite us."

She stressed her determination to use Holyrood's existing powers and promised an early policy review, with a focus on children's issues.

Labour MSP Drew Smith said: "If Nicola Sturgeon wants to move forward after so long as Alex Salmond's deputy she needs to show that she has learned the lessons of the referendum which her old boss has found so difficult to heed. That must mean being prepared to accept that Scotland remaining within the United Kingdom is the settled will of the Scottish people."

Scottish Conservative deputy leader Jackson Carlaw said: "This confirms that a vote for the SNP in 2016 is a vote for another independence referendum - that is not what the majority in ­Scotland want."