Angela Rayner has criticised Jeremy Corbyn, saying the Labour leader "didn't command respect", as she labelled the party's Brexit position as "awful".
Ms Rayner, who is the favourite to become Labour's deputy leader, told ITV News Political Correspondent Paul Brand that she'd be tougher than Mr Corbyn in several ways.
"I'm more bombastic, more focused and more sharp, and I would expect more discipline in a way that Jeremy didn't," she said.
"He didn't command respect, and he therefore wasn't able to command that collectivism in the Labour Party."
Touting her leadership credentials, she said she has "respect" and "support" right across the Labour Party and claimed she is able to "resonate with people in the country in a way that Jeremy doesn't."
And in another bid to distance herself from Mr Corbyn, she suggested - unlike leadership candidate Rebecca Long-Bailey - that the current leader should not be admitted to the shadow cabinet once he's been replaced.
During the interview with Paul Brand, Ms Rayner also appeared on camera with her mother for the first time, as the pair opened up about depression and poverty.
When asked about Mr Corbyn's potential role on the frontbench, she said: "I think now the opportunity should be for the next generation to come forward."
"I do think we have to show that we're different and that we're bringing new talent in and we have to show that we do want to do that and change as a party," she added.
She also attacked his election manifesto, Brexit position and security stance.
"Our Brexit position was awful, people did not accept where we were at on that," she told Paul Brand, "and our manifesto was too much, people just didn't think it was credible."
And she claimed she would be more "pragmatic" than Mr Corbyn in terms of security.
She said: "I think I'm stronger on security, I've always felt quite strong about that."
Adding: "I don't think he was weak, but I think he had a more international view of things, whereas I'm more pragmatic.
"I understand the international context, but I also understand most people in this country just want to know that you're going to keep people safe and look after them and that's my primary."
She went on: "A lot of people didn't think that's what Jeremy's primary aim was."
For more from Angela Rayner, listen to the Acting Prime Minister podcast, which will be published before 10pm Monday