It will now be put to members at a special party conference in March.

Leader Nicola Sturgeon said the second option had been included in the motion in the interests of having a “full and open debate”.

She said: “Given the significance of this decision for both the party and the country, it is important that this debate is a full, free and open one – which is what the draft resolution seeks to enable.

“It sets out – as I did last June – the option of contesting the next Westminster election as a de facto referendum.

“However, in the interests of a full and open debate, it also sets out the alternative option of contesting the next Scottish Parliament election on this basis.”

She added: “While this will be a debate on the process of securing independence, it is one that will be guided by a fundamental principle – that the future of Scotland must and will be decided by the people of Scotland, not by Westminster politicians.”