Scottish Liberal Democrat leader Willie Rennie has claimed "the national interest can be saved" by a second referendum on the UK's final Brexit deal.
Mr Rennie insisted people were rethinking their decision to leave the European Union as he urged Labour and the SNP to back the campaign for another vote.
He said leaked government analysis showing economic growth would be hit by Brexit was changing public opinion.
The Lib Dem leader was addressing the David Hume Institute in Edinburgh as part of series of speeches by Scotland's party leaders.
An ICM survey conducted for the Guardian newspaper and published last month found 47% of people would favour having a final say on Brexit once the terms of the UK's departure are known.
"In 2018 people are thinking again," Mr Rennie said.
"Now in 2018 we can feel the early consequences of Brexit and have also seen the evidence of what is likely to happen next.
"We have seen how the architects of Brexit in the Conservative Party have no clue what they want or how they are going to get it."
He added: "It is therefore little surprise that people are beginning to think that they have had enough of it."
Nicola Sturgeon has said a second referendum is becoming "hard to resist" but she has stopped short of joining the campaign for one.
Jeremy Corbyn has previously indicated he does not support a final deal ballot, while shadow chancellor John McDonnell said on Sunday it would be better to have a general election.
"The time is coming fast when people should have the freedom to refuse a bad Brexit deal," Mr Rennie said.
"People need to get on board. The national interest can be saved."
The Lib Dem leader also used his address to link the economic impact of Brexit to the issue of immigration.
"Ensuring EU citizens are free to continue to live and work here is essential for maintaining that population growth, which underpins future economic growth and the sustainability of our public services," he said.
The UK Government's pledge to cut immigration "poses a direct threat to the country", he added.
"The Conservative Government faces a choice: damage the economy or admit they were wrong on immigration."