Ash Regan, the third candidate competing to become the Scottish National party leader and first minister, has said she believes Scotland will be allowed its independence without a referendum if enough voters support pro-independence parties in an election. Regan’s campaign launch took place on Friday before the midday deadline for nominations. The Scottish health secretary, Humza Yousaf, and the finance secretary, Kate Forbes, are the other two candidates in the race. She denied that this strategy was a rehash of the “de facto referendum” plan that was shelved by the SNP last week after Nicola Sturgeon announced she was stepping down as leader. Regan’s campaign team confirmed she had received more than 100 nominations, from at least 20 party branches, pitting her against Yousaf, widely seen as Sturgeon’s preferred candidate, and Forbes. At an event in North Queensferry that was short on domestic policy proposals, Regan said she would in effect scrap the gender recognition reform bill, which has been blocked by the UK government, by refusing to appeal against Westminster’s decision. Regan had resigned as community safety minister under Sturgeon in protest against the bill, becoming a flag-carrier on the issue for SNP rebels at Holyrood. The pro-independence Scottish Green party, which is in coalition with the SNP in government, has warned that its two ministers will resign in protest if the bill is dropped as it is a “red line” policy in their cooperation agreement. Regan said she would also accelerate Scotland’s road-widening programme and slow down the move away from North Sea oil and gas extraction – two other policies the Greens would oppose. Regan described her independence mandate plan as a “voter empowerment mechanism” that would be placed as “line one” of an SNP manifesto at the next election, although she later said she would first put her proposal to a party conference if she became leader. Under her policy, if pro-independence parties won a majority of seats and votes at a general election “the international community will see that and I think that clear instruction should be enough to trigger those negotiations”, she said. Her proposal is in opposition to the stances taken by Yousaf and Forbes, and has been heavily criticised by SNP MPs. A number of opinion polls show it is disliked by voters, which suggests the SNP would fail to win an election if that was the central theme of its campaign. Rishi Sunak, as well as his predecessors and Keir Starmer, have all said the approach misunderstands the purpose of a general election, which is based on a slate of ideas. The Spanish government has repeatedly said it would only recognise a legally founded referendum supported by the UK government. For the SNP and the yes movement, those positions highlight the paradox they face in trying to achieve independence. Since opinion polls show a lack of consistent majority support for independence, with the no vote currently in the lead, Yousaf argues independence can only be gained through a legally secure route. With Jo Cherry as the only SNP MP in Westminster to have backed Regan’s campaign, the new candidate acknowledged she was “definitely the outsider” in the contest. Regan said she wanted to build a fresh mass movement with every other pro-independence group, including Alex Salmond’s breakaway Alba party, but agreed her stance on gender recognition, roadbuilding and oil drilling risked alienating the pro-independence Greens. Sturgeon negotiated the government cooperation agreement with the Scottish Greens largely because it cemented a pro-independence majority in Holyrood, where the Greens have seven MSPs. Without them, the SNP would be one vote short of a majority. “The Greens have already said they might not want to work with a candidate such as myself, or a candidate such as Kate Forbes,” Regan said. “So it’s for the Greens to decide what they want to do next. We need to sit down with them, have a conversation and see where that goes.”