The Labour Party has descended into chaos with the party's only Scottish MP one of several high-profile figures to quit the shadow cabinet in an open revolt against Jeremy Corbyn's leadership.

Ian Murray, who represents Edinburgh South, wrote to Mr Corbyn saying: "Dear Jeremy, I came into politics because I wanted to serve the people of Edinburgh South and help create a more equal, more prosperous, and fairer country. It has always been clear that the only way to achieve this is for Labour to be in Government.

"The last week has shown the almost irreparable damage done to our country by this Conservative Government. The Prime Minister has gambled the future of our country to fix his party. We are now on the way to the EU exit door and there is a grave risk that the UK will break up. This would not have happened had we had a Labour Government.

"With the result of the referendum on the European Union, the country faces a deeply challenging time ahead. That demands a strong opposition capable of holding the Government to account, helping to secure the best possible deal for Scotland and the UK and building to win any future general election. I do not believe that can be achieved under your leadership. Therefore, it is after much thought, and with regret, that I resign from the Shadow Cabinet.

"I want to say that I have always supported you and regard you as a kind, principled and genuinely decent man. I agreed to serve in the Shadow Cabinet for the good of party unity, and to honour my responsibility to Scotland after the General Election in 2015. In Scotland, we face significant uncertainty and potentially more constitutional upheaval. Kezia Dugdale is doing an excellent job but needs a strong UK Labour Party to support her. I believe that we can only win again as a party when the UK Labour Party is able to articulate the case for progressive policies the length and breadth of the United Kingdom. I also believe we can only do that under new leadership.

"I have always expressed my thoughts directly to you as I think it is important to be honest and open with each other. However, I do not feel this has been reciprocated. I also feel the way some colleagues have been treated has been unfortunate. I will therefore return to the backbenches to serve my constituents and fight Scotland's corner from there. When writing this letter all I could think of was the words of John Smith, 'The opportunity to serve our country - that is all we ask'. We need to talk to the wider country to achieve that and not just our comfort zones. I thank you for giving me the opportunity to be in your shadow cabinet. Best wishes, Ian Murray"

Shadow health secretary Heidi Alexander was the first member of Jeremy Corbyn's top team to quit after Hilary Benn was sacked from the shadow cabinet.

Lucy Powell's letter resigning as shadow education secretary read: "Dear Jeremy, It is with regret I am writing to you to resign from the Shadow Cabinet. I have enjoyed working closely with you and holding the Government to account as Shadow Education Secretary.

"Working with parents, teachers and MPs across the House we have forced the Government to drop their detrimental plans to force all good and outstanding schools to become academies.

"I have challenged the government on their failure to recruit enough teachers, their failure on school place planning and highlighted the huge budget pressures schools are now facing.

"I didn't know you before you became leader but I have come to know you and found you to be a decent, principled and kind colleague.

"However, it is increasingly clear that your position is untenable and that you are unable to command the support of the Shadow Cabinet, the Parliamentary Labour Party and, most importantly, the country.

"Given the big challenges faced by our country and our Party over the coming months, and the possibility of an imminent general election, I do not have the confidence that you can bring the Party together, lead us to a General Election and be an effective Opposition.

"We must champion our communities and build a politics that unites the country after the division of the EU referendum campaign. The Labour Party faces an existential threat. The task in front of us is immense. We have, over many years, lost the support of our traditional communities. While I don't blame you personally for that, I do not believe you understand their concerns sufficiently to re-engage with these communities.

"The people we represent need a strong Labour Party and we need to effectively challenge a Tory Party which is lurching ever rightwards. This is a bigger task than any one person but it does require strong leadership and a united team.

"Thank you for the opportunity to serve in the Shadow Cabinet in a role that I am passionate about. I hope now, you will reflect on the breadth of concern being raised about the quality of your leadership and for the good of our Party and for the good of the country stand down as Labour leader. Yours sincerely, Lucy Powell MP, Member of Parliament for Manchester Central."