The SNP faces a challenge to persuade voters to back independence over the next year but the polls can be turned around, the Deputy First Minister has said.

Nicola Sturgeon issued a rallying call as party activists gather in Perth for their annual four-day conference.

With less than 11 months until voters decide whether Scotland should remain part of the UK, the conference will be used to argue the case for independence.

Decisions should be taken north of the border to get the best for Scotland, Ms Sturgeon said.

She said that the Yes campaign can turn around the polls.

Earlier this month a poll by TNS put support for independence at 25%, with 44% in the No camp and 31% saying they do not know how they will vote.

Ms Sturgeon said: "It's a challenge. I cast my mind back to January 2011 when the SNP was something like 15 points behind Labour in the opinion polls. Just a few months later we went on to win the Scottish election and score an overall majority in that election."

"The message I take from that is if your argument is right, if you pitch your argument properly to voters, then polls can be turned around, and that is our challenge over the next year.

"We have got to win the argument that Scotland should be independent. That boils down to a decision about where decisions are best taken. Are they best taken here in Scotland by governments that are elected by the people of Scotland, or are they best taken at Westminster by governments that often we reject?

"We've shown through the Scottish Parliament that where decisions on health, on education, on the justice system are taken in Scotland then we take better decisions. We take good decisions that are in line with the priorities of the people of Scotland.

"So the argument is, let's complete that journey, let's complete those powers because that's what independence is, it's completing the powers of the Scottish Parliament."

Derek Mackay, the SNP's business convener, said Scotland must vote for independence to bring about ''an end to bad government from Westminster".

Mr Mackay, also the Local Government Minister at Holyrood, said the welfare cut known as the bedroom tax is a ''graphic illustration of the Yes case that the best government decisions for Scotland are those made in Scotland''.

Mr Mackay said: ''The incompetence and cruelty of the bedroom tax, and the soaring number of people dependent on food banks in resource-rich Scotland, show why we cannot afford to leave powers over welfare, the economy and pensions in Westminster's hands, and why we need to take these decisions in our own parliament.

''A Yes vote is for good government with independence and an end to bad government from Westminster."