Boris Johnson was wrong to suggest that Labour and the SNP have done a deal on a second Scottish independence referendum, Nicola Sturgeon has said.

“There is no deal with Jeremy Corbyn”, the SNP leader said at a campaign event in Dundee on Wednesday, after the Labour leader dismissed as “nonsense” Johnson’s accusation, made during Tuesday night’s television debate.

Sturgeon described the ITV head-to-head between the leaders of the two main UK parties as “a debate in which the SNP and Scotland were talked about a lot but not allowed to be in the room”.

She added: “I do believe if the parliamentary arithmetic enables this, Jeremy Corbyn is not going to turn his back on an opportunity for a UK Labour government just because he’s determined to block the right of the Scottish people to choose their own future.”

On a visit to Scotland last week, Corbyn challenged Sturgeon to support a minority Labour government after dismissing her calls for a progressive alliance to thwart the Tories in Westminster.

But Sturgeon in Dundee reminded voters that the SNP, not Labour, were the main rivals to the Tories in Scotland. “In all the 13 seats the Conservatives hold here, it is the SNP who are the challengers. If the people of Scotland want to make sure Boris Johnson does not get a majority, if they want to see a progressive alliance formed with Scotland’s interests front and centre and the Tories locked out of government, only a vote for the SNP can deliver that outcome,” she said.

During last week’s visit, Corbyn was asked to clarify his stance on a second independence vote, with Labour aides explaining that the party’s position could change if the SNP again won a majority of seats in the 2021 Holyrood elections.

Sturgeon joked that Corbyn’s “red line” on an independence referendum “has been looking pretty pink. If you can make any sense out of what he has said, he has kind of accepted the principle of Scotland being in charge of its own future; he’s quibbling now about the timescale.”

She said Westminster would be “engulfed in Brexit chaos for years to come, with long-term damage to Scotland guaranteed,” but she baulked at comparisons between the time taken to resolve Brexit and the potential upheaval of independence.

Insisting that “there was nothing inevitable about the mess that the Brexit process has become”, Sturgeon said: “[In 2014] we had very detailed plans in place to manage our way through a transition … let us not allow the charlatans who were dishonest with people over Brexit to somehow suggest that constitutional change has to be that way.”

She added: “Travelling around the country I detect a real enthusiasm and optimism around the SNP’s message in this election. People in this election, whatever their views on independence, have the chance to make it clear that the future of our country should be determined here, not by Boris Johnson.”