Nicola Sturgeon has called for the Scottish parliament to be given permanent powers to hold subsequent referendums on independence from the UK.

Describing the SNP’s success in last week’s general election as an “unarguable mandate by any normal standard of democracy”, Scotland’s first minister confirmed on Thursday morning that she had formally written to Boris Johnson to request the powers to legally stage another referendum under section 30 of the 1998 Scotland Act.

Alongside this, the SNP leader published a 38-page document that also sets out draft amendments to the statute, which would devolve the right to hold votes on leaving the UK to Holyrood.

Insisting that she was not advocating for a third independence referendum – “not least because I think when Scotland gets the chance to vote again, it will vote for independence” – she refused to rule one out for ever, underlining that no first minister could bind the hands of their successors over the right to self-determination.

Entitled Scotland’s Right to Choose, the publication argues that there has been a “material change of circumstance” since the independence referendum of 2014, based on “the prospect of Scotland leaving the EU against its will and what EU exit has revealed about Scotland’s position within the UK”.

Launching the document at an event at her official residence of Bute House in Edinburgh, Sturgeon said she “fully expected to get a flat no” from Westminster initially.

“I’m going to stand my ground. I fully expect today we will get the flat no of Westminster opposition, but that will not be the end of the matter and Boris Johnson should not be under any illusion that it is.”

Johnson will use the Queen’s speech on Thursday to confirm that a second independence referendum next year would be a “damaging distraction”, while setting out investment in the Scottish economy.

Describing the Tory strategy as “self-defeating”, Sturgeon insisted that continued refusal to allow the Scottish people their right to choose would only boost support for independence.

She added: “I am not simply firing off a letter to Boris Johnson; I am publishing a detailed and considered case.” She said that when she spoke to Johnson immediately after the election results, he had committed to engaging seriously with the proposals.

Since securing 47 of Scotland’s 59 Westminster seats with an increased vote share of 45% last Thursday, Sturgeon has described the general election as a “watershed moment” and declared that the country could not be “imprisoned in the UK against its will”.

But, despite Westminster’s chaotic handling of Brexit and Johnson’s unpopularity among Scottish voters, the expected long-term boost to support for independence has not materialised, with polls showing support averaging at around 48%.

On Thursday afternoon, a separate bill setting out how referendums in Scotland will be run was voted through its final stage at Holyrood. But this framework bill does not set the date or the question on the ballot, which have to be specified in further primary legislation.

Much of the afternoon’s debate centred around whether a previous referendum question – such as the yes/no format of 2014, which critics argued favoured the affirmative side – has to be reassessed by the Electoral Commission if it is being asked again within two parliamentary terms. In the end, a compromise was reached, which allows MSPs to vote to consult the commission regardless of timing, but which could in reality be blocked by a pro-independence majority.

The Electoral Commission confirmed on Monday that the bill had accepted its recommendation of a minimum 10-week campaign period. Added to the required 26-week lead-in period, that would mean a referendum would need nine months from the passing of legislation in Holyrood to polling day, making the chance of one in 2020 highly unlikely.