A former Labour first minister has urged Jeremy Corbyn to throw the party behind efforts to stop Britain leaving the European Union.
Henry McLeish issued a plea to Labour's leadership to use the "natural majority" for remaining in the EU at Westminster to "derail and ultimately defeat" Brexit.
Mr McLeish, who served as Scotland's first minister from 2000 to 2001, also said it is the "final call" for the party on the issue of the constitution before Scotland moves towards independence.
Addressing an audience at the Edinburgh International Book Festival about his new book Citizens United, Mr McLeish described Brexit as a "national act of self-harm" with "simply no benefits".
He said: "Can I also say to Labour's leader at this point, if Labour had half a campaign running before the referendum, Brexit would not have won.
"The second point then is an invitation to Jeremy and (shadow chancellor) John McDonnell to put their own ideas of the EU and Europe behind them and use the House of Commons and/or another referendum to make sure that there's a proper debate on this empty box that we voted on, once it is filled up.
"We are internationalists, Labour. By instinct and history we believe that protections for employees should be in place and not squandered in the return of legislation to Britain.
"There are so many pressing needs that Labour could embrace and I believe that the leadership of the Labour Party should now four-square be behind remaining."
Mr McLeish, who has previously said he could back Scottish independence in the event of Brexit, said he is "nearly there" on the question of an independent Scotland but added that he still hopes federalism could be "the key to unlocking the constitutional door for Labour in Scotland".
He said: "We (Labour) have done ourselves a whole lot of damage by pretending that this will go away. It isn't going to go away and Labour must now rejoin enthusiastically the constitutional debate and not press for a vote on independence, another referendum on independence, but a referendum on the future of Scotland, and that could have another question.
"I make an appeal to the Labour Party, do not be afraid of the constitutional question.
"You cannot go around and say to Scots, we're against having another referendum. If Scots want another referendum they shall have another referendum.
"The way to defeat independence if you're Labour is to engage in the battle, engage in the referendum, win your case, win the vote. And as a democrat, that's what they should be doing."
Mr McLeish said he believes that if there was nothing other than independence on the table, Scotland could move towards another referendum on the issue within three to five years.
"This is the final call for Labour before Scotland moves towards independence," he said.
But the former first minister said he also questioned whether it is already "too late" for federalism as it appears to be "an abstract debate" that is "not even on the radar screen of Westminster".