Diane Abbott: Labour MPs scuppered Jeremy Corbyn at PMQs
Labour MPs have been accused of deliberately undermining leader Jeremy Corbyn by refusing to cheer him at Prime Minister's Questions.
Owen Smith - who is challenging for the party leadership - told The Guardian Mr Corbyn had let new PM Theresa May off the hook at Wednesday's session.
But Jeremy Corbyn ally Diane Abbott blamed Labour MPs.
She told BBC Radio 4's Today programme they had "sat on their hands" and sulked instead of getting behind him.
"If Owen Smith wants Jeremy to score over Theresa May in Prime Minister's Questions, he needs to talk to his colleagues," said the shadow health secretary.
"They refuse to cheer, they sit on their hands, they sulk, they chat among themselves, and some of these Labour MPs need to understand, it's not about supporting Jeremy as a person, it's about going into the chamber for Prime Minister's Questions and supporting your party.
"When Theresa May came in she got huge cheers from the Tory benches. When Jeremy came in there was silence."
She added: "If your own side isn't behind you it's really difficult to hit your stride. I thought he did fine but if Owen Smith is worried, first and foremost, talk to Labour MPs and get them to support Jeremy in the chamber."
Mr Smith told The Guardian he was "furious" about Mr Corbyn's "useless" performance at Wednesday's big set-piece event, which saw Mrs May make her debut at Prime Minister's Questions.
"Jeremy is just not up to the job of taking them on at the dispatch box. I don't think he enjoys it; I don't think he's robust enough at arguing Labour's case," he said.
Mr Smith said that instead of putting together a credible government in waiting, Mr Corbyn had made Labour a "laughing stock".