Kezia Dugdale has said Nicola Sturgeon's calls for clarity on the terms of Brexit for Scotland is ridiculous, as the SNP keep changing their mind on EU membership.
Holyrood is to begin debating the possibility of a second Scottish independence referendum on Tuesday.
This follows last week's announcement by Scotland's First Minister that she would petition the Scottish Parliament to hold a second vote because there had been a "significant change" in Scotland's circumstances in the wake of the Brexit vote.
Ms Dugdale, the leader of the Labour Party in Scotland, visited the talkRADIO studios for an interview with Julia Hartley-Brewer and said: "We spent two years debating the independence question where we covered all the issues.
"85% of people voted, one of the highest turnouts, and they said no. Voters want that respected.
"Sturgeon’s saying Brexit’s offering a whole new dynamic, but she says there has to be clarity in the choice Scotland faces - when the SNP had four different stances on EU membership in the last week."
Ms Dugdale was particularly scathing about suggestions that Scotland could join the European Free Trade Association, rather than the EU.
She said: “The Efta arrangement, for instance, is an odd thing to argue. It means we’d give away power but have no say over the rules which govern us.
"For a party to exist and talk about the soverignty of a nation, that’s madness."