The SNP will publish a new strategy on Thursday, designed to keep its plans for an independence referendum alive until after the General Election.

First Minister Alex Salmond is expected to announce plans to publish the SNP's Referendum Bill in draft form.

That would mean the party could put the proposals out to consultation, with a closing date set for after the country goes to the polls.

If the Bill were to be published in its final form, it would go straight in front of a special Holyrood Committee for consideration.

However, the SNP worried that would sound the paper's death knell within weeks, because all three opposition parties have confirmed they will vote against it.

The proposals are expected to support a two question referendum, where voters would give their support to either full independence or increased powers under devolution.

However, that would mean Ministers could consult on the specifics of the devolution question. It is unclear whether it would refer to the recommendations of the Calman Commission, formed by Labour, the Tories and the Lib Dems, or whether the powers be extended further than that.

The consultation could potentially be used to influence the setting of the referendum questions.

However, the opposition parties have blasted moves to delay the publication of a final Bill for consideration.

Scottish Labour leader Iain Gray accused the SNP of running scared and branded the move "a humiliating climb down"

He said: “The facts are that Alex Salmond is in a desperate place. His administration has run out of steam, his ministers are under pressure and he is frightened that his last remaining key manifesto pledge is set to be rejected.  

“They know they cannot defend their dismal record on jobs and economic recovery. It is time for the First Minister to stop playing games and treat the electorate with respect. He should put up or shut up on the referendum.”

Scottish Tory leader Annabel Goldie added: “This is a desperate attempt by Alex Salmond to divert attention from the troubles swamping his government. His independence bill is doomed to failure, is a waste of taxpayers' money and Parliamentary time.

“He needs to start acting like a First Minister and not an opposition party in Government. He should stop dithering and either ditch the bill or introduce it.”