A Liberal Democrat government would revoke Article 50 and stop Brexit "on day one", leader Jo Swinson has vowed.
In her first speech to the party's conference as leader, she reiterated its policy of overturning the law ensuring the UK will leave the EU.
A no-deal Brexit would be like "burning your house down", Ms Swinson added.
The East Dunbartonshire MP also appealed to Scottish voters to reject the SNP and join a "bigger movement for change" across UK to stop Brexit.
Ahead of an expected general election, Ms Swinson said she could not wait to take on Boris Johnson, Labour's Jeremy Corbyn and Brexit Party leader Nigel Farage.
The Lib Dems currently have 18 MPs - a figure boosted by recent defections - but it would require a seismic shift in the electoral landscape for them to win power.
Nevertheless, Ms Swinson received a standing ovation when she told the conference she wanted to be prime minister, adding: "There is no limit to my ambition for our party."
On Tuesday, as the Supreme Court began hearing two appeals relating to the suspension of Parliament, Lib Dem conference delegates backed an emergency motion calling for the suspension of Parliament to be reversed.
Lord Newby, Lib Dem leader in the House of Lords, said the prime minister had prorogued Parliament on "a transparent lie" in a way that had reduced the Queen to "a ceremonial rubber stamp".
Earlier at the conference Lib Dem members voted overwhelmingly to back her proposal for a manifesto pledge to revoke Article 50 if the party came into power with a majority government.
Which on the face of it, is not likely. OTOH, stranger things have happened as im sure you have all noticed.