A former Labour home secretary has called on the party to reinstate the membership of Alastair Campbell after admitting he also voted Liberal Democrat.
Charles Clarke, a senior figure in the New Labour government, said he took a "one-off decision" to vote for the Lib Dems in the recent European Parliament elections.
Mr Campbell, Tony Blair's former spin doctor, was expelled from the party on Tuesday after he said he voted for the Lib Dems.
In a statement, Mr Clarke said Labour "should immediately withdraw its expulsion of Alastair".
He 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.
"I also voted Liberal Democrat. This was a one-off decision because of the hopeless incoherence of Labour's position, particularly that of Jeremy Corbyn, on Brexit.
"I have been a Labour Party member for 47 years and have never before voted anything but Labour. I was chair of the Labour Party in 2001-02.
"I have consistently argued against those who, often in understandable despair at the Labour leadership's abandonment of Labour's fundamental values, have either resigned from the Labour Party or joined another party."
Mr Clarke said he would vote for "Labour's excellent MP for Cambridge" in the next general election.