Jess Phillips told the Cheltenham Literature Festival that she would consider running to be Labour leader if Jeremy Corbyn stands down after a general election.
Mr Watson also said the party must push for a new referendum to take place before a general election.
Chukka Umunna said he had spoken to a 'substantial minority' of Labour MPs who 'simply would not countenance' Jeremy Corbyn becoming Prime Minister.
Senior Labour figures are accused of interfering with the disciplinary process investigating claims of anti-Semitism.
In a letter to Theresa May, Jeremy Corbyn said their talks have been "unable to bridge important policy gaps".
Stuart Davies, a member of Clwyd South Conservatives, shouted at the Prime Minister to resign as she began a speech to Welsh Tories in Llangollen. The National Convention don't want you, we don't want you,” shouted Mr Davies, who described himself as a loyal Conservative. Afterwards, he told journalists that Mrs May should resign “now”.
Rebecca Long-Bailey was responding to fresh anti-Semitism claims against Jeremy Corbyn.
After weeks of debate, they are simply reiterating their plan to hold open the “option” of a public vote if they can’t get their own deal or a general election. Brexit has sucked out any content or meaning from the British electoral system. If you believe we should both be supporting an alternative Brexit and seeking to stop it: vote Labour.
Labour MPs and MEPs are signing a letter to the party's ruling NEC calling for its EU election manifesto to commit to a second referendum.