Defiant Liberal Democrat leader Charles Kennedy condemned the critics gunning for his job yesterday - with remarks which appeared to be aimed squarely at Birmingham MP John Hemming.
He attacked opponents for being "full of themselves" and contrasted their approach with his "experience" and "mature leadership".
Mr Hemming, the Lib Dem MP for Yardley, was elected only six months ago.
Earlier this week, the Birmingham MP revealed he would like to lead the party, but admitted he would have to wait because it was "too soon" to launch a challenge.
But Mr Kennedy launched a stinging counter-attack during his set-piece speech at the party's annual conference in Blackpool.
He said: "Others may have become so full of themselves that they think they're full of better ideas about the leadership.
"But based on experience, I believe that what I have set out is the sensible and genuine and mature way to lead a political party."
Mr Kennedy told delegates he wouldn't stand down, and said he believed he could lead the Lib Dems to election victory.
He said: "It's my ambition to lead the first government in the liberal tradition of the 21st century." Later he added: "I'm up for it."
Mr Kennedy also repeated his support for plans to privatise the Royal Mail - which led to him losing a key conference vote after Mr Hemming led a rebellion against him.
The Lib Dem leadership argued that selling the Royal Mail would raise enough money to save post office branches from closure.
But Mr Hemming convinced the activists at the conference to reject the plan.
Mr Kennedy said the proposals were "not left, not right, but liberal", arguing the party should stick to "liberal values".
The speech covered a range of issues, but some of the strongest language was reserved for criticism of Tony Blair over the Iraq war.
He said: "Along with President Bush, Tony Blair's so-called war on terror has been so badly implemented that it has actually boosted the terror threat, not diminished it.
"When they should have been concentrating on bringing a proper peace to Afghanistan, Bush and Blair waged war in Iraq. The Prime Minister's pride should not get in the way of finding a solution." British troops must be bought home, he said, adding: "The invasion of Iraq has created a volatile, fragmented country now facing the threat of civil war."
He said that following the London bombings, he wanted to work with the Government on anti-terror legislation.
However, he could not support some of the Government's proposals - in particular, to allow police to detain people for three months without charge.
"That's a prison sentence by any other name," said Mr Kennedy.
He also attacked plans for a new offence of "glorifying terrorism" as " vague" and "unworkable".
Mr Kennedy highlighted the party's success, telling delegates: "Today we have MPs in almost every major city - Manchester, Leeds, London, Bristol, Cardiff, Birmingham, Glasgow, Edinburgh."