Scottish Labour MSPs have said they "deplore any attempts to undermine" the party's position on a second independence referendum, in a stinging rebuke of John McDonnell.

The statement agreed by a majority of the Scottish Parliamentary Labour party expressed "serious concerns" with the Labour leadership south of the border.

It comes after the shadow chancellor said he would not support blocking powers to the Scottish Government to hold such a vote.

He made the comments at two Edinburgh Fringe events on consecutive days, despite sparking an angry backlash within Scottish Labour, leading to a meeting with party leader Richard Leonard.

McDonnell's stance contradicted Scottish Labour policy in opposing another referendum, with Edinburgh Labour MP Ian Murray slamming it as "utterly irresponsible".

In their statement, Scottish Labour MSPs condemned "the apparent change in Labour's position on a matter of vital importance to the future of Scotland".

It said: "The Scottish Parliamentary Labour party has already opposed a divisive and unnecessary second independence referendum and will campaign tirelessly to ensure Scotland remains part of the United Kingdom.

"The people of Scotland were told that the 2014 independence referendum was a once-in-a-generation contest."

The statement went on: "We deplore any attempts to undermine the official policy position of the Scottish Labour party and we express serious concerns about an apparent change in Labour's position on a matter of vital importance to the future of Scotland and of the Scottish Labour Party itself.

"Scottish party policy is very clear - that is opposition to a second independence referendum.

"There is therefore an urgent need for the UK party leadership to engage constructively with the Scottish party leadership on the issue of the party's stance on the future of Scotland."

It added: "We expect all Scottish Labour MPs and MSPs to vote in accordance with party policy."

Leonard and McDonnell met on Wednesday morning, where the Scottish Labour leader said he made clear his position on the issue.

But at his second Fringe event in two days later on Wednesday, the shadow chancellor reiterated his view that a Labour government preventing a second referendum would play into the SNP's hands.

McDonnell said: "I'm not being set up by Nicola Sturgeon to blame the UK Government for blocking the will of the Scottish people - that's too trite a political manoeuvre that's been taken on at the moment.

"In the situation we're in at the moment, my view is that we will not be blocking a proposal.

"The best way forward in all of this is to elect a Labour government. We'll demonstrate what we can do and then I think the Scottish people won't be interested in another referendum.

"But if they ever do come back, my view is you can't be in a situation where you block it."

SNP MSP George Adam branded Scottish Labour's position "increasingly bizarre".

He said: "It's hard to think of a time in recent years when they've been more vocal than this week's frenzied backlash to the suggestion that people in Scotland should have a choice over their own future.

"The UK leadership recognises that democratic right - why don't Labour in Scotland? Labour's position in Scotland is fundamentally anti-democratic."

Adam added: "If Labour continue to side with the Tories in denying Scotland's right to choose our own future, then Labour's fate is well and truly sealed - they'll be wiped out completely."

Scottish Liberal Democrat leader Willie Rennie said: "The open divisions in the Labour party on independence show they are not in a position to stand up for Scotland's place in the UK.

"The Labour leadership's scheming to get power at the expense of the country shows they can't be trusted.

"I feel sorry for Labour MSPs who fought long and hard to keep Scotland in the UK but they are being ignored now by Jeremy Corbyn and John McDonnell."