Tony Blair's former political operations director has slated Jeremy Corbyn, branding him "incoherent" and "unpatriotic".
John McTernan said the Labour leader had made the party "unelectable", and was responsible for its worst election result since 1935.
"Jeremy chose an incoherent position on Brexit. Jeremy is the leader, Jeremy is unpatriotic, he doesn't care about British security, overseas security or security on the streets, as he showed over the Salisbury poisoning," he told talkRADIO's Julia Hartley-Brewer.
"He was the leader, he was totally in charge and he crafted the worst election result the Labour Party has had since 1935."
His comments come as the party's general secretary, Jennie Formby, suggested the process to appoint a new leader should begin on January 7.
A number of senior figures in the party's leadership have already given their backing to shadow business secretary, Rebecca Long-Bailey, to replace Mr Corbyn.
But Mr McTernan warned against appointing Ms Long-Bailey, suggesting instead Jess Phillips or Lisa Nandy.
"Does Labour really want to win? Choosing Rebecca Long-Bailey is a statement that Labour really doesn’t want to win. Labour just wants to take the 2019 manifesto and go left again," he added.
"You’ve got to move away from anyone that has served in the current shadow cabinet, so Keir Starmer and Emily Thornberry would have to be out."
He continued: "If the party doesn’t want to change, I won’t see a Labour government in my lifetime."
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