Labour deputy leader Tom Watson said it is “spiteful” to expel people from the Labour Party and called for an “amnesty” for members who did not support the party at the European elections.
His comments came after Alastair Campbell, Tony Blair’s former spin doctor and a leading campaigner for a second referendum, was ousted from Labour after he backed the Liberal Democrats at the polls.
Mr Watson condemned the decision to expel Mr Campbell, saying “intolerance” would not be a part of the Labour Party, and that members should be listened to, not “punished”.
“It is very clear that many thousands of Labour Party members voted for other parties last week,” he said.
“They were disappointed with the position on Brexit that a small number of people on the NEC inserted into our manifesto. They were sending the NEC a message that our position lacked clarity, and they were right.
“It is spiteful to resort to expulsions when the NEC should be listening to members.
“The politics of intolerance holds no future for the Labour Party. A broad church party requires pluralism and tolerance to survive.
“There should be an amnesty for members who voted a different way last week.
“We should be listening to members rather than punishing them.”
Mr Campbell has claimed “senior” figures in Jeremy Corbyn’s office recommended voting against Labour as support for his decision to shun the party in the European elections grew.
On Tuesday night Mr Campbell said members of Mr Corbyn’s staff were among those who sent “many, many messages of support” for his decision.
Hours earlier, Charles Clarke, the former Labour home secretary and party chairman, said he also voted Liberal Democrat in the election, while ex-defence secretary Bob Ainsworth said he voted Green.
And Baroness Boothroyd also revealed she did not vote for the party at the European elections.
The former Common Speaker, who is a supporter of a second referendum, said: “The Labour Party seems incapable of making positive leadership decisions of late. Fence-sitting seems to be in vogue.
“But the decision to expel Alastair Campbell from membership of the Party is the daftest, most insensitive decision of all.
“For the first time in my long political life I didn’t vote Labour in the European elections and there are no prizes for guessing where my vote went.”
Speaking outside his north London home, Mr Campbell said he will appeal against the expulsion and warned that Labour faces “oblivion” unless it clarifies its Brexit position.
“I think that there are people in Jeremy Corbyn’s office, senior positions in Jeremy Corbyn’s office, who have recommended voting against the Labour Party,” he said.
“You can interpret the rules in all sorts of different ways, but one thing I know is I’m not going to leave the party just because some random email comes in telling me that I’ve been expelled.”
In a tweet he added: “Among many, many messages of support have been some from Corbyn’s office, shadow cabinet, MPs, union leaders and party staff including one telling me there is a mountain of emails from members who responded to mobilisation email by saying no to campaigning and not voting Labour.”
He said it “remains to be seen” whether other members who admitted opting against Labour at the polls would also be expelled.
Mr Campbell described his rapid expulsion as “strange” and said “people will inevitably draw the contrast with the lack of rapidity in dealing with cases involving anti-Semitism”.
Labour said “support for another political party or candidate is incompatible with party membership” but declined to say whether Mr Clarke would also be ousted.
In a statement, Mr Clarke said Labour “should immediately withdraw its expulsion of Alastair”.
The former party chairman, a member for 47 years, added: “I was not aware that Alastair had voted Liberal Democrat in the European election until I heard him say so on television on Sunday evening.
“His expulsion from Labour Party membership is a disgrace and only compounds Labour’s current political difficulties.”
Mr Campbell, a key player in the New Labour era, declined to rule out shunning the party again in a snap general election and said it would “depend” on its Brexit policy.