Ed Miliband's leadership has come under fire again with the resignation of Scottish Labour Party leader Johann Lamont, as she claimed her colleagues "do not understand the politics they are facing".
The Glasgow MSP used her exit to criticise the party's leadership across the UK, and accused Westminster of trying to manage Scotland "like a branch office of London".
She added: "Colleagues need to realise that the focus of Scottish politics is now Holyrood, not Westminster.
"There is a danger of Scottish politics being between two sets of dinosaurs… the nationalists who can't accept they were rejected by the people, and some colleagues at Westminster who think nothing has changed."
It marks another setback for Ed Miliband ahead of next year's General Election - already, a group of Scottish Labour activists are pushing for their party to enjoy complete autonomy from London.
Speculation over Ms Lamont's leadership has grown since the referendum, with one senior aide confessing Scottish Labour needed to rediscover its "sense of purpose".
Nicola Sturgeon, due to become the First Minister in November once she replaces Alex Salmond as leader of the SNP, warned that "Scottish Labour really is in meltdown" if rumours of its tensions with Westminster were true.
Ms Lamont alluded to this in her resignation letter to Jamie Glackin, chair of the Scottish Labour Party.
She wrote: "Some, including senior members of the party, have questioned my place in this new phase. In order that we can have the real discussion about how we take Scottish Labour forward, I believe it would be best if I took myself out of the equation and stepped down as leader."
In reaction to Friday's news, a Scottish Conservative spokesman said: "Johann Lamont's resignation has shown the complete chaos at the heart of Ed Miliband's operation in the starkest possible terms.
1/6
-
Gallery: Who Will Be The Next Scottish Labour Leader?
Some of the politicians tipped to succeed Johann Lumant: Anas Sarwar is the MP for Glasgow Central, and will assume the role of acting leader of the Scottish Labour Party until a ballot takes place
-
Kezia Dugdale became an MSP for the Lothian Region in 2011, and also writes a column for the Daily Record, the same newspaper used by Johann Lumont to criticise the Labour Party
-
Gordon Brown, the former Prime Minister, has also been tipped for the role. He returned to front-line politics by encouraging the public to vote No in the independence referendum
-
Jim Murphy had insisted he was not going to begin a leadership challenge against Johann Lumont, but all that could now change now she has resigned
-
Douglas Alexander, the MP for Paisley and Renfrewshire South, already has a meaty role in Westminster as shadow foreign secretary
-
Jenny Marra is another MSP who entered Holyrood in 2011. She is deemed to have an outside chance of becoming the Scottish Labour leader
"The man isn't fit to run a village fete, never mind the UK."
In a statement, Mr Miliband said: "Johann Lamont deserves significant credit for the successful No vote in the Scottish referendum campaign.
"She has led the Scottish Labour Party with determination."
Earlier this week, Scottish Labour was described as "going through a period of reflection" after the referendum, which saw large numbers of the party's supporters vote to leave the UK, despite the overall majority of Scots backing the union.
Ms Lamont, who took over as leader in December 2011, is the second Scottish party leader to resign since September's vote - and made her comments during a Daily Record interview.
The first to quit, Alex Salmond MSP, said: "The fact that Scottish Labour are now going to have their fifth leader since the SNP took office in 2007 indicates that their problems are not about personalities - they are much more deep-seated than that.
"It was always very clear that Johann Lamont was never able to be meaningfully in charge of Labour in Scotland, and that is laid bare in dramatic fashion in her resignation comments."
Gordon Brown, who is one of the favourites to succeed the mother-of-two, said: "I am sorry to hear than Johann has resigned.
"She brought determination, compassion and a down-to-earth approach to the leadership and deserves great credit for taking on the challenge after 2011.
"I wish her well in the future."
Meanwhile, Tony Blair, another former Labour Prime Minister, has had to deny rumours that he privately believes Mr Miliband will not win the next General Election.