NICOLA Sturgeon has placed the SNP on to a war footing for a second independence vote as she revealed that a draft referendum bill will be published next week.

The First Minister, opening the SNP conference, issued a series of thinly-veiled threats to Theresa May as she indicated a new referendum would be fought - and won - if the UK Government rejects a string of demands over a post-Brexit deal.

She called on Ms May to "prove" that Scotland would be an equal partner within the UK and is set to request powers for Holyrood to strike international deals, more control of immigration and the transfer of control over policies now within the EU's remit, such as fishing and farming. She also strongly suggested that a 'hard Brexit', that would see Scotland taken out of the single market, would prove unacceptable.

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Ms Sturgeon said: "My message to the Prime Minister is clear. Scotland didn't choose to be in this situation - your party put us here. In 2014, you told us Scotland was an equal partner in the UK. Well, the moment has come to prove it. If you value the UK - as you say you do - it's up to you to prove it can work for Scotland.

"But hear this - if you think for one single second that I'm not serious about doing what it takes to protect Scotland's interests, then think again.

"If you can't - or won't - allow us to protect out interests within the UK, then Scotland will have the right to decide, afresh, if it wants to take a different path."

She added: "I am determined that Scotland will have the ability to reconsider the question of independence - and to do so before the UK leaves the EU - if that is necessary to protect our country's interests. So I can confirm today that the Independence Referendum Bill will be published for consultation next week."

A consultation will be launched following the publication of the bill, with Ms Sturgeon to then make a decision over whether it will be formally introduced at Holyrood where there is a majority of pro-independence MSPs.

The announcement drew a huge ovation at the conference, held at Glasgow's SECC. Closing her speech, Ms Sturgeon warned that ahead of a second referendum Yes supporters would have to "engage the arguments with a fresh eye and an open mind."

But she added: "If the choice we face is an inward looking, insular, Brexit Britain, governed by a right wing Tory party, obsessed with borders and blue passports at the expense of economic strength and stability...

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"Or a progressive, outward looking, internationalist Scotland, able to chart our own course and build our own security and prosperity, then know this - that is a case we will win."

With the question of a second referendum to dominate the SNP conference, Ms Sturgeon also issued a call for unity with some in the party calling for a quick vote on independence and others urging caution.

It came as Alex Salmond, Ms Sturgeon's predecessor, called for a new referendum even if polls are level. The former First Minister said: "There have been six opinion polls since the European vote. Three of which have shown a majority for independence and the other three have all shown an increase from 45 per cent [support].

"Will Nicola Sturgeon push the button on a referendum if support for independence is, say, 50:50 or at that level? Well, I hit the button for a referendum when support was 27 per cent. Why would she be reluctant on a much larger level than that?"

Ms Sturgeon reiterated that if a new referendum is called, it would take place before the UK formally breaks ties with the EU, currently expected early in 2019.

She told delegates: "There's not a day that passes just now without someone advising me to hurry up, and there's not a day that passes without someone advising me to slow down. Welcome to my world.

"But the responsibility of leadership is to act in the best interests of our country as a whole. The morning after the EU referendum, I said that I'd be guided at all times by a simple, clear test. What is best for the people of Scotland?

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"That's the principle I will continue to be guided by - and I know I can count on your support every step of the way."

Asked about Ms Sturgeon's announcement to publish an independence referendum bill next week, Ms May's spokeswoman said: "This issue was addressed in 2014. What we should all be focused on now is working together as a United Kingdom to get the best deal as we leave the EU."

Kezia Dugdale, the Scottish Labour leader, accused Ms Sturgeon of putting independence over education, health or tackling poverty.

She said: “Nicola Sturgeon’s top priority is to divide our nation once again. But our country is already divided following the Tories’ reckless Brexit gamble and we should not be seeking further divisions.

“Our economy is in trouble, and the last thing we need is the uncertainty of another independence referendum.

“It is little over two years since more than 2million Scots voted to reject independence. Nicola Sturgeon promised us that she would respect that result and said the referendum would put the issue to bed for a ‘generation’.

“She should keep that promise. Scottish Labour will vote against any referendum Bill that she brings before parliament.

“In her speech to the SNP conference, Nicola Sturgeon had an opportunity to tell the country how she will face the challenges of the future. Instead, she resorted to an argument of the past.”