Douglas Alexander, who served as Secretary of State for Scotland under Tony Blair, said Labour's position on an IndyRef2 should reflect the opinion of the majority of Scots - and party members north of the Border - who do not want another vote.
He spoke out after Jeremy Corbyn rowed back yesterday from an initial refusal to grant another referendum on the constitution during his first term in office.
The UK Labour leader had told reporters there would be “no referendum in the first term for a Labour government” if he took power following next month’s general election - even if the SNP won a majority of Scottish seats.
Hours later, Mr Corbyn told reporters that he instead did “not countenance” another independence referendum in “the early years” of a Labour government.
"I think Labour's position should be where the majority of us are as Scots - which is that we want to remain in the UK, and we want the UK to remain in the EU. We feel Scottish, British, and European. But what we've seen, to put it kindly, is that ambiguity has not been a friend to the Labour party since the referendum in 2014, or indeed the Brexit referendum in 2016.
"Having simultaneously left doubts in the minds of the 62 per cent of us who voted to remain in the EU, and the 55 per cent who voted to remain in the UK, it helps explain why we have seen the start of this general election with such tough numbers for the Scottish Labour party.
"I think the overwhelming bulk of the Scottish Labour party membership are clear that an independence referendum is not what most of us, as Scots, want. The SNP have been trying to position themselves as seeing Brexit as their priority to some voters, putting Jeremy Corbyn in Downing Street to other voters."
In response to Mr Alexander's comments, Conservative MSP Annie Wells said: “Douglas Alexander is the latest in a long line of Labour MPs and former ministers to criticise Jeremy Corbyn’s shambolic policy on the union.
“It’s quite clear that Mr Alexander thinks the Labour position on the union is weak and ‘ambiguous’. This is an obvious betrayal of the thousands of Labour unionist voters who have been abandoned by Mr Corbyn.
“The Scottish Conservatives are the only party who will stand up for the Union and the only party that can defeat the SNP."