Gordon Brown has admitted he had made mistakes as Prime Minister and promised: "I will do better."
But his pledge failed to convince his most vocal party critic, former Home Secretary Charles Clarke, who said he did not believe the Labour leader was capable of improving his performance and called on him to quit.
In an interview two days ahead of the crucial conference speech on which his future as Prime Minister may depend, Mr Brown insisted he remained the right man to shepherd Britain's economy through global financial turmoil.
He dismissed suggestions he might by out of 10 Downing Street by Christmas and insisted he would not "bail out". Far from plotting against him, his Cabinet were "pretty united", he said.
Although he admitted mistakes over the abolition of the 10p income tax rate and promised to learn lessons from the fiasco, Mr Brown said he and Chancellor Alistair Darling had taken "the right decisions" on issues like the Lloyds/HBOS merger and the ban on short-selling, anticipating the development of events and acting ahead of other countries such as the US.
And he told BBC1's Andrew Marr Show: "I was Chancellor for 10 years. I am in a position to deal with the national and international events that are happening. I have got the experience to deal with these events.
"I happen to think I am better prepared to deal with it than perhaps anyone, because you can't deal with it by slogans and PR and good soundbites, you have to deal with it by the wisdom of the decisions you make."
Asked by Marr if he had made mistakes, he said "Yes", adding: "Of course I always want to do better and I will do better."
Mr Clarke - who has previously called on Brown to stand aside for a new leader if he cannot turn Labour's fortunes around - said he was "very sceptical" that he was capable of transforming his performance and told BBC1's The Politics Show: "Therefore I think he probably should stand down."
And he warned Labour MPs they could not afford delays in resolving the leadership issue: "The one thing which I think is completely unacceptable is to ignore the real political situation in the country and drift along, assuming we will somehow pull it around ... It won't be all right on the night."
