The shadow chancellor has said Labour would not block a second Scottish independence referendum after Nicola Sturgeon hinted at forming a pact to keep the Conservatives out of government.
In an interview with journalist Iain Dale at the Edinburgh Festival Fringe, John McDonnell said any decision about holding a vote would be up to the Scottish Parliament.
It followed comments reported on Tuesday by Scotland’s First Minister that the SNP would “always want to be part of a progressive alternative to a Tory government”.
Mr McDonnell said: “It will be for the Scottish Parliament and the Scottish people to decide that.
“They will take a view about whether they want another referendum. Nicola Sturgeon said by late next year or the beginning of 2021.”
He added: “We would not block something like that. We would let the Scottish people decide. That’s democracy.
“There are other views within the party but that’s our view.”
However, Mr McDonnell said on Tuesday: “The Scottish Parliament will come to a considered view on that and they will submit that to the Government and the English Parliament itself.
“If the Scottish people decide they want a referendum, that’s for them.”
The comments come after the publication of an opinion poll suggesting the majority of Scots could back independence.
Mr McDonnell’s view contradicts that of Scottish Labour leader Richard Leonard.
In an interview on the BBC’s Sunday Politics Scotland in March, Mr Leonard said if Labour took power in Westminster the party would refuse to grant a “Section 30 order” giving Holyrood the power to hold another vote.
Mr Leonard added: “What we said in the manifesto at the 2017 election was that there is no case for, and we would not support, a second independence referendum.”
Speaking to the Guardian, Ms Sturgeon said: “I have fought two general elections now as SNP leader, and, in both of them, I have been pretty candid.
“We would always want to be part of a progressive alternative to a Tory government. That remains the case.
“I think in politics you’ve got to be careful. But it would not be my intention, to go into a formal coalition.
“I said that in 2015 and 2017 – that’s not a new thing. But some kind of progressive alliance that could lock the Tories out of government. It wouldn’t be a blank cheque-type scenario.”
The senior Labour frontbencher said he was “extremely worried” about new Prime Minister Boris Johnson.
He added: “I think he’s reckless and I think he’s unstable and I will move heaven and earth to stop a no-deal Brexit.”
Scottish Liberal Democrat leader Willie Rennie said: “It’s bad enough with Boris Johnson bungling on Brexit and independence but to have the Labour Party’s (shadow) chancellor piling in makes it a whole lot worse.
“It’s clear only the Liberal Democrats are robustly standing up for Scotland’s place in the UK and the EU.”
Labour MP for Edinburgh South Ian Murray attacked Mr McDonnell’s comments.
He said: “These are utterly irresponsible comments from John McDonnell that betray our party’s values.
“The Labour Party is an internationalist party founded on a vision of solidarity and we should never seek to appease nationalists, whether they be for Brexit or Scottish independence, who want to divide communities and people.”
Mr Murray also tweeted: “Scottish Labour opposes a damaging and divisive Scottish independence referendum. The policy is set by the Scottish Labour Party and outlined in our last manifesto.
“John McDonnell must clarify his unhelpful freelancing immediately.”
Scottish Conservative leader Ruth Davidson tweeted: “I feel for those Labour voters that stood side by side with major figures of their party and against the forces of nationalism in 2014. Know that the @ScotTories will always stand up for our United Kingdom.”
Following the comments, Labour MP Stella Creasy tweeted: “Nationalism is antithesis of socialism – to prioritise passports over principles isn’t progressive.
“Egalitarian devolution isn’t about separation but how by working together as nations within the UK each stronger and more successful. Labour abandons such commitment at our peril.”
SNP MSP Jenny Gilruth said: “With a no-deal Brexit approaching, we urgently need clarity from Richard Leonard and Scottish Labour.
“It’s a bit embarrassing that Westminster Labour politicians have done more than their Holyrood colleagues to defend the democratic rights of the people of Scotland.”
She added: “Unless Scottish Labour join the SNP in defending Scotland’s right to hold an independence referendum, they’ll be lending their backing to the jobs-wrecking Tory Brexit and will continue their slide into complete irrelevance.”