London mayoral hopeful Tessa Jowell says Chuka Umunna felt responsible for media attention on his family, which included one instance where a reporter was waiting on his mother's doorstep.
As Political Correspondent Libby Wiener reports, the young Labour prospect withdrew from the race citing the intense scrutiny of the press, which tipped him as an early favourite for the contest.
A former Labour minister says Britain is "almost the only country in the world" where intense media coverage would put a candidate off running for public office.
Speaking after Chuka Umunna's withdrawal from the leadership race, Ben Bradshaw, former Culture Secretary, said: "If it is true that his extended family and his extended circle of friends were coming under this kind of scrutiny, that says something very sad about our political culture."
ITV News Political Correspondent Libby Wiener reports on the shadow business secretary's decision to pull out of the running.
Shadow business secretary Chuka Umunna has quit the Labour leadership race, dealing another blow to a party still reeling from defeat at last week's general election.
Mr Umunna, the MP for Streatham, had been tipped as the favourite in the contest, but dropped out just three days after announcing he would run.
In a statement, he said he was unprepared for the level of "scrutiny and attention" he had been subjected to since then, though it is still unclear exactly what prompted his U-turn.
ITV News political correspondent, Lewis Vaughan Jones reports:
Labour politicians have voiced their regret at the withdrawal of shadow business secretary Chuka Umunna from the leadership contest.
Mr Umunna, the MP for Streatham, pulled out saying he had not been prepared for the level of scrutiny his life would come under by taking part in the race.
Both current and past Labour MPs, including former Home Secretary Jacqui Smith, have said they are "sorry" he felt the need to withdraw.
It's hard to imagine scale of intrusion when it turns in your direction. V sorry about Chuka but understand https://t.co/SMvXDZpeap
I believe @chukaumunna would have been a transformational candidate who could have offered something big enough to meet the challenge ahead
Shadow business secretary Chuka Umunna has announced his withdrawal from the Labour leadership race, saying he was not prepared for the level of "scrutiny and attention" it would attract.
Sources close to the Streatham MP insisted his withdrawal was not due to any negative story which he feared might appear in the media.
In a statement, he said:
I... thought I understood the scrutiny and attention a leadership contest would bring.
However since the night of our defeat last week I have been subject to the added level of pressure that comes with being a leadership candidate.
I have not found it to be a comfortable experience.
One can imagine what running for leader can be like, understand its demands and the attention but nothing compares to actually doing it and the impact on the rest of one's life.
Consequently after further reflection I am withdrawing my candidacy.
I apologise to all those who have kindly supported and encouraged me to do this and for disappointing them. I know this will come as I surprise to many but I had always wondered whether it was all too soon for me to launch this leadership bid - I fear it was.
Most importantly, I continued to have very real concerns and worry about this bid's impact on those close to me.
He apologised to everyone who had supported him to date, and vowed to continue his work as MP for Streatham, as well as playing a role in the Shadow Cabinet.
Labour MP and Shadow International Development Secretary Mary Creagh is set to join the race to be elected Labour leader, making her the fifth person to declare their candidacy.
Shadow home secretary Yvette Cooper is the latest Labour member to announce her bid to succeed Ed Miliband as leader of the party.
She joins Andy Burnham, Liz Kendall and Chuka Umunna, who have all announced they will stand for the leadership.
Labour have confirmed the new party leader will be announced in September after an election campaign.
Shadow home secretary Yvette Cooper has said she wants to become Labour's next party leader because she wants to "make life better" for British families.
Announcing that she would be joining Chuka Umunna, Liz Kendall and Andy Burnham in Labour's upcoming leadership contest Cooper pledged that she was in politics "to make change happen" and wanted to improve the lives of the British public.
In an article for the Daily Mirror Cooper wrote: "I don’t want to be the next leader of the Labour Party just because there’s a vacancy, I want to make life better for Britain’s families.
"It isn’t enough to say we can stop bad things happening, we need to show how good we can be for people too.
"This four-month leadership election can’t be just a debate about the future of our party as some have suggested. It has to be a debate about the future of our country."
Yvette Cooper has announced that she plans to run for the Labour Party leadership.
The shadow home secretary made the announcement that she would be entering the race to become party leader in an exclusive article that she has written for tomorrow's edition of the Daily Mirror.
Andy Burnham has announced that he is running to become leader of the Labour party.
The shadow health secretary made the announcement in a video posted on YouTube.
He said the party needed to "rediscover the beating heart of Labour" and a leader whose voice could "carry into all nations and regions of the UK" after a general election that had left the country "divided".
"Someone who people can relate to, who understand their lives. I am that person, I can unite this country and that is why I am standing to be leader of the Labour party," he said.
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