Nicola Sturgeon warned Jeremy Corbyn on Sunday not to “pick up the phone” for a coalition government unless he was willing to grant Scotland a second independence referendum.

The Labour leader has said that a new independence poll is not a good idea but he has not ruled out the possibility. Sturgeon has said that she will formally request a new referendum later this year, although it is not clear who will be the UK’s prime minister by that time.

The SNP is planning to campaign in the next elections on a promise to lead Scotland towards a second independence referendum. The Conservative government has already said that the 2014 referendum is binding and will not grand another.

But SNP hardliners suggest that if Scotland is not granted a second referendum, the national government will begin negotiations on its own mandate. In that case, the next elections could be run as a referendum on independence, as the UK braces to leave or has already left the EU. Others activists have called for an unofficial referendum, similar to the one held in Catalonia in 2017.

Ms Sturgeon, the Scottish first minister, has repeatedly said that a Section 30 order would need to be granted by the UK government and the SNP must have a clear majority of the Scottish seats in a general election to advance the cause of independence.