One of Labour's 2014 election candidates has written a stinging open letter to David Cunliffe, saying he would leave the party if Mr Cunliffe won the leadership contest and challenging Mr Cunliffe to promise to step out of politics if he lost.
James Dann was Labour's candidate in Ilam and wrote a guest post on the Public Address website, saying that during the election campaign a number of people he door knocked had told him they would not vote Labour while Mr Cunliffe was its leader.
Others had refused to put up hoardings with Mr Cunliffe's face on them.
Mr Dann said in the letter that he had supported Mr Robertson in the last leadership contest but after Mr Cunliffe won he had swung in behind, including organising Labour's annual conference soon after, driving Mr Cunliffe around during the Christchurch East byelection, and giving him credit for a strong personal campaign.
However, he said he would not be part of the party if Mr Cunliffe was leader.