Humza Yousaf has said a win in Scotland for the Scottish National party in the next general election would be a mandate to apply further pressure on Westminster for Scottish independence. The proposal, made by the SNP leader as he addressed party members gathered in Dundee, falls short of the de facto referendum strategy favoured by his predecessor, Nicola Sturgeon. “If the SNP does win this election then the people will have spoken,” he said. “We will seek negotiations with the UK government on how we give democratic effect to Scotland becoming an independent nation.” With any legal route to a referendum stalled by the UK government’s repeated refusal to grant Holyrood the requisite powers to hold a second vote, Yousaf promised: “We can break the logjam with Westminster by mobilising the power of the people at the general election.” Setting out his own preferred route at a daylong event intended to allow party members the chance to discuss independence strategy, Yousaf said the first line of the next manifesto should read, “Vote SNP for Scotland to become and independent country”, but underlined that his plan A remained holding a legal referendum. Speaking to the media after the speech, he denied this was in substance no different from any other mandate the SNP had fought for in previous elections: “It’s a very simple proposition we’ve never put on line one, page one of the manifesto, making it really clear that if you vote for the SNP you’re voting for Scotland to become an independent country,” he said. If Westminster continued to deny Scotland a second referendum, he said: “That’s a question for the UK parties. If this is a voluntary union, they’ve got to prove it.” But this appears to be a significant retreat on the de facto plan put forward by Sturgeon after the supreme court ruled Holyrood could not hold a second vote without Westminster’s consent last October. Sturgeon had suggested that if more than half of votes were cast for parties in favour of independence, the Scottish government would regard that as a mandate to pursue negotiations. But Yousaf clarified that a win in Scotland would be measured in terms of parliamentary seats rather than percentage of votes, and that success would mean yet again pressing whichever party was in Downing Street for the means to hold a second vote. But with the Conservative and Labour leaderships doubling down on their opposition to a second independence referendum in the runup to a likely general election next year, Yousaf said: “We will not be waiting for Westminster to respond; we will take our destiny into our own hands.” A general election win for the SNP would be a mandate to “ensure we as a government are ready to negotiate our independence”, he added, by setting out a detailed document on the transfer of powers from Westminster to Holyrood, conducting a nationwide consultation of a draft interim constitution and establishing an envoy position in Brussels to prepare the ground for Scotland to rejoin the EU. Yousaf was speaking at the first substantial SNP gathering since he replaced Sturgeon as leader and the party was rocked by the arrests of senior figures, including Sturgeon, as part of Police Scotland’s investigation into party finances. Yousaf said “there is no route to independence other than through a lawful democratic process”. During his leadership campaign, Yousaf made clear his own doubts about the de facto strategy, about which many SNP MPs also had grave reservations. He also signalled a shift in focus away from legal process towards building popular support to a consistent majority. Polling shows Scotland remains split on the question, with support for independence on average 48%, according to the website What Scotland Thinks, little different from what it has been for most of the time since the last Holyrood election. But polling also suggests the SNP’s recent internal difficulties have had minimal effect on support for independence, despite support for the party itself falling, with Scottish Labour the beneficiary. This marks a sea change in Scottish politics, with voters now willing to decouple the constitutional question from their electoral choices. After a day of panel discussions and workshops, and with plans for a summer of pro-independence activism, the party will not make a final decision on its strategy until its main autumn conference in October. Yousaf spoke to delegates after tributes were paid to the SNP trailblazer Winnie Ewing, who died aged 93 earlier this week.