Rhondda MP Chris Bryant quits Labour shadow cabinet
Rhondda MP Chris Bryant has become the latest Labour shadow cabinet member to resign in protest at Jeremy Corbyn's leadership over the EU referendum.
The former shadow Commons leader tweeted: "We need someone new to unite and lead Labour."
In his resignation letter he told Mr Corbyn: "If you refuse to step aside I fear you will go down in history as the man who broke the Labour Party."
But Mr Corbyn said he will not "betray the trust of those who voted for me".
In the letter, which was also published on Twitter, Mr Bryant wrote that Mr Corbyn's "inability to give a clear, unambiguous message to Labour voters" had "significantly contributed to the result" of the EU referendum.
Mr Bryant wrote: "Sadly, the referendum has shown that you and your team cannot run an effective national campaign and that you do not command the support of the country."
He said: "I urge you, because you are a decent man to do the decent thing and take the only action that can avert potential disaster by stepping aside.
"If you do so I believe future generations will praise your selflessness."
Mr Bryant was the latest of a string of shadow cabinet members who resigned in protest at Mr Corbyn's leadership.
In a statement Mr Corbyn said: "I regret there have been resignations today from my shadow cabinet. But I am not going to betray the trust of those who voted for me - or the millions of supporters across the country who need Labour to represent them."
He added: "Those who want to change Labour's leadership will have to stand in a democratic election, in which I will be a candidate."
Earlier Aberavon Labour MP Stephen Kinnock warned his party will suffer heavy losses if Mr Corbyn leads it into a general election this year.
Mr Kinnock, asked on BBC Sunday Politics Wales if he feared that many MPs could lose their seats, said: "That is absolutely central to our concerns.
"I do not see him as a negotiator with the skills and experience that we need to take us forward at this unprecedented time.
"I accept that the membership gave Jeremy a huge mandate, but that was then and this is now. Everything has changed."
Mr Kinnock added: "We have to ensure that we go into that general election with a leader who is right in the context of a post-Brexit referendum United Kingdom."
But Darren Williams, secretary of the left-leaning Welsh Labour Grassroots movement, told BBC Radio Wales it was "disappointing that Labour isn't uniting around Jeremy Corbyn".
Wrexham MP Ian Lucas said he wrote to Mr Corbyn urging him to stand down after his local constituency party passed a motion of no confidence in the leader.
He told BBC Radio Wales he was disappointed by the sacking of Hilary Benn as shadow foreign secretary.
"It's symptomatic of the fact unfortunately the present leader is not capable of leading the Labour Party effectively at this time of national crisis," he added.
Former Welsh Secretary Lord Hain said: "It's been very evident for a while that the majority of Labour-inclined voters do not think Jeremy is capable of winning the next election for us.
"That is the reality which cannot be ignored. That's the issue that needs to be confronted by party members who voted for him."
But in a blog post, Newport West Labour MP Paul Flynn accused shadow cabinet members of "playing party games" while jobs were in peril.
He wrote: "It's a disgrace that political parties are playing self-indulgent games with orchestrated resignations on the hour as part of an organised treachery."
Mike Hedges, Labour AM for Swansea East who supported Corbyn's leadership bid, told BBC Wales: "Less than 12 months ago Jeremy Corbyn won the biggest mandate of any Labour leader.
"This referendum had members of the Labour party on different sides.
"I do not understand why some MPs are blaming Jeremy Corbyn for the referendum result. We should be uniting as a party behind the leader to hold the Tory party to account."