Labour has clarified that it will only review Alastair Campbell’s expulsion from the party as part of the appeal process, with Jeremy Corbyn saying it looked forward to hearing his explanation for voting for the Liberal Democrats.

Campbell, a former director of communications to Tony Blair, has said he voted for the Lib Dems in the European elections because they were a pro-remain party and backed a second referendum. He is appealing against the decision to kick him out of the Labour party.

After a number of Labour figures – from the former home secretary Charles Clarke to Cherie Blair – and many grassroots members challenged Labour to expel them too for voting Lib Dem, there was a suggestion that the party could reverse its decision.

Shami Chakrabarti, the shadow attorney general, had appeared to say Campbell’s expulsion would be reviewed.

Speaking to BBC Radio 4’s Today programme on Thursday, she said: “Now there will be a review, which is appropriate. I don’t want to cut across this review, I’m not part of that process. I would not like to see this drag on.”

Asked whether she believed Campbell should be allowed to rejoin the party, Chakrabarti said: “That will depend on what he says about his intentions.”

However, eight hours later, Labour released a statement playing down the significance of any review, saying the decision would only be looked at in the context of the appeal process.

Corbyn was also asked about the decision in an interview during a visit Dublin to talk to Irish politicians about Brexit.

“It’s a question of what Mr Campbell said two days before the election in which he apparently appeared to be supporting the Liberal Democrats and whilst he is a member of the Labour party that is clearly not acceptable,” Corbyn said. “But we look forward to hearing what Alastair has to say about this and look forward to his support in the future.”

Campbell subsequently tweeted that “God knows what that is supposed to mean”. Campbell made public that he voted Lib Dem two days after the results were announced.

His expulsion from Labour has prompted anger among some party members, including the deputy leader, Tom Watson, who called it “spiteful” and said members who voted for other parties in last week’s elections should be accorded an amnesty.

Clarke called for Campbell’s reinstatement, adding that his expulsion only compounded “Labour’s current political difficulties”.

Clarke said: “I also voted Liberal Democrat. This was an one-off decision because of the hopeless incoherence of Labour’s position – particularly that of Jeremy Corbyn – on Brexit.”

Fiona Mactaggart, a former MP for Slough, also voted for the Lib Dems. It was “time for us all to declare: ‘I am Spartacus,’” she said. The former defence secretary Bob Ainsworth said he had voted against Labour for the first time in his life – opting to support the Green party instead.

Others within Labour however, described the decision to expel Campbell as merely a matter of applying party rules consistently. Dawn Butler, the shadow women and equalities secretary, said on Tuesday that members who admitted voting for another party were “automatically excluded”.

“It’s just part of the rule book. Everyone knows that,” she added.

Momentum, the grassroots group of Corbyn supporters, said at the time: “Alastair Campbell’s ‘sexed up’ dossier started the Iraq war and left 1 million dead. Being kicked out of the party is the least he deserves.”

Campbell, a prominent campaigner for a second referendum, said he had voted tactically to try and make the leadership alter its position on Brexit.

After his expulsion on Tuesday, he said: “I think it’s a strange thing to do, and I think people will inevitably draw the contrast between the lack of rapidity in dealing with cases involving antisemitism.”

On the same day, the Equality and Human Rights Commission launched a formal investigation over whether the party had unlawfully discriminated against, harassed or victimised people because they were Jewish.

Labour came third behind the Brexit party and the Lib Dems in the European elections, a result many have blamed on its inexplicit Brexit position.

On Wednesday, Corbyn pledged that Labour would back a public vote on any Brexit deal put to parliament.