The SNP’s new Westminster leader has put economics firmly at the centre of the debate over Scottish independence, arguing that the Yes camp will only win when Scots believe they will be better off away from the UK.

Marking a decisive shift in emphasis for his party, Ian Blackford, a former banker, insisted that prosperity was key to winning the debate over Scotland’s future. He said: “We will win independence when we can persuade the people of Scotland that their economic future is better as an independent country.”

Mr Blackford’s approach differs significantly from that pursued by Nicola Sturgeon, the SNP leader. The first minister has talked about the need for Scotland to stay in the European single market but she has not put the