Alastair Campbell’s expulsion from the Labour Party should be reviewed, the shadow attorney general has said.
Tony Blair’s ex-communications chief was thrown out for saying he had voted Lib Dem in the European elections because of his party’s Brexit stance.
Baroness Chakrabarti told the BBC that Labour members who had backed rivals should “come forward” and discuss their differences with the party.
Mr Campbell said he was “confident I could win an appeal”.
The party’s share of the vote fell to 14% in last week’s European elections and several senior figures have blamed its nuanced position on Brexit.
Speaking on BBC Radio 4’s Today programme, Baroness Chakrabarti said she hoped Mr Campbell and other Labour members who had expressed public support for other parties could “come forward and talk about their future intentions and the case can be reviewed”.
“Merely voting for another party is not in itself a grounds for exclusion or expulsion or anything like that and I want the large numbers of people who did that last week for heart-felt reasons to rest assured,” she said.
Baroness Chakrabarti also said: “Political parties have rules about people who support other parties, but I hope this case will be reviewed.”
Labour leader Jeremy Corbyn said Mr Campbell’s actions were “not acceptable”, adding: “We look forward to hearing what Alastair has to say about this and look forward to his support for Labour in the future.”
Mr Campbell made his decision to vote for the Lib Dems public on the BBC’s election night broadcast, accusing Labour of “letting its own supporters down” in “failing to devise a policy the country could unite around” over Brexit.
Responding to Baroness Chakrabarti’s comments, Mr Campbell tweeted: “Pleased, if true that my ‘expulsion’ from Labour is being ‘reviewed.’”
However, he added that he had “not heard anything from the governance unit”.
The decision to kick Mr Campbell out of the party was criticised by other Labour figures including the deputy leader Tom Watson who called it “spiteful”.
He called for “an amnesty” for members who voted for other parties adding – “we should be listening to members rather than punishing them”.
A number of other senior Labour figures have since confirmed they also voted for different parties in the European polls.
Former Home Secretary Charles Clarke said he had voted Lib Dem, as did ex-MP Fiona Mactaggart, while former Defence Secretary Bob Ainsworth said he had voted Green.
Labour said supporting another party was “incompatible” with membership.
A spokeswoman said the issue was not about voting, but Mr Campbell “using media appearances to advertise and encourage support for another party”.
Last week former Conservative Deputy Prime Minister Lord Heseltine was suspended from the parliamentary party after admitting he was planning to vote for the Liberal Democrats in the elections.
Concerning Labour’s position on Brexit, Baroness Chakrabarti said her party would not necessarily back Remain in a future EU referendum.
“That would depend on what the deal was,” she said.
“Was it going to be a Labour deal with the closest possible relationship with Europe, or was it going to be a deal that we thought less than satisfactory?
“We want to break the stasis in this country with a general election or a public vote.”