Scottish Liberal Democrats leader Willie Rennie has said he would vote to block holding another independence referendum.
Mr Rennie said holding another poll would be “divisive, unhelpful” and not good for Scotland’s future.
His comments contrast to Labour leader Jeremy Corbyn, who said on Saturday that another referendum would be “absolutely fine”.
Nicola Sturgeon has repeatedly warned a fresh vote is “highly likely”.
Speaking on the BBC’s Sunday Politics Scotland programme, Mr Rennie said: “We stood on a platform last May when we said we would oppose independence and oppose another independence referendum.
“You and others have criticised me and our party before for not sticking to our word. We’re going to stick absolutely to our word on this.”
Asked if he wished to block a referendum taking place – rather than simply opposing Scottish independence – Mr Rennie answered: “No independence referendum, either at Westminster or in the Scottish Parliament – that’s the view of the Liberal Democrats.
“You’re asking me to go against what I believe. I believe that we shouldn’t have another one because it’s divisive.”
He added: “I would vote against the Conservatives at every possible opportunity just like I’d vote against another independence referendum.”
Mr Rennie said the Brexit process alone was going to cause “economic chaos” and so he would oppose any moves to authorise another independence referendum he said would bring “even more chaos”.
“Of course I’m not against democracy but we’ve had the democratic experience three years ago. We decided we wanted to stay,” he said.
The Scottish Lib Dem leader also accused Mr Corbyn of a “casual indifference” to the future of the United Kingdom.
“He just doesn’t seem to care about the United Kingdom sticking together.
“I know that’s not the view of my colleagues in the Scottish Labour Party. They must be tearing their hair out this morning at what he said yesterday.
“I find it astonishing that he can be so casual about the future of the United Kingdom just as he’s been so casual about the future of the European Union.”
Mr Corbyn told the Press Association on Saturday it was not the job of Labour “to prevent people holding referenda”.
A spokesman for Mr Corbyn later told the BBC: “Jeremy reaffirmed our position today that if the Scottish Parliament votes for a referendum, it would be wrong for Westminster to block it.
“Labour continues to oppose a further referendum in the Scottish Parliament and would campaign against independence if one were held.”
But Scottish Labour leader Kezia Dugdale has said her party would oppose any attempt to hold a referendum.
The party’s justice spokeswoman, Jackie Baillie, also described his comments as “misguided and irresponsible”.
Commenting on Mr Corbyn’s remarks, Scottish Conservative leader Ruth Davidson said: “At this time, people in Scotland who voted No to independence in 2014 want pro-UK leaders to demonstrate resolve against the SNP’s threat of a second referendum.
“Instead, the Labour leader has demonstrated that he is happy to let the SNP roll over him.
“It is a complete betrayal of the many thousands of voters who once looked to his party to defend our United Kingdom.”
Mr Corbyn’s remarks came amid speculation that Ms Sturgeon is about to demand a Section 30 order from Westminster, allowing another legally binding vote on Scotland’s place in the UK to be held.
Prime Minister Theresa May has so far avoided saying whether or not she would grant permission – instead saying only that she does not believe a second referendum should be held.
Wille Rennie wants Scottish independence poll blocked}