JULIA Gillard has revealed the reason she knifed Kevin Rudd for the leadership a year ago was because he had lacked a sense of purpose or plan for the future.

As her approval rating sits at a record low amid speculation about her leadership, Ms Gillard indicated it was Mr Rudd's political paralysis that led her to make the biggest decision of her life.

In an interview with The Daily Telegraph to mark a year since the coup that deposed Mr Rudd, Ms Gillard denied it was the opinion polls that drove her to challenge him.

"We had lost a sense of purpose and plan for the future," Mr Gillard said.

"We didn't have a clear plan as to how we were going to deal with a set of difficult questions or a clear plan generally about where the government was driving towards.

"What I've done as Prime Minister is inject that sense of clarity of purpose."

Last night, the polls showed Ms Gillard in dire straits.

She is on only a 31 per cent approval rating and twice as many voters prefer Mr Rudd.

The Neilsen poll today also has her government in crisis.

Labor's primary vote has fallen four points to 27 per cent - the lowest of any federal party in the poll's 39-year history - and the Coalition on 49 per cent.

Ms Gillard's own judgment is also being called into question with several senior ministers privately describing the decision to announce a $12 million ad campaign for a carbon tax as lunacy.

The final decision to make the snap announcement on Thursday had not been taken to Cabinet this week, although it had previously been approved by the Cabinet.

"It was crazy stuff," one minister said.

"I don't know what they were thinking. Taxpayers are not going to thank us for this."

Ms Gillard, who yesterday attended her 13th funeral for a soldier since becoming PM, said there had been testing times in the past year from the finely balanced parliament, and the summer of disasters and deaths in Afghanistan had been the low point.

Mr Rudd has also refused to remain silent on the events that ended his leadership.

In an exclusive interview, he called for the grass roots membership of the Labor Party to seize back control from the factional warlords who helped depose him.

"(It's) the ability of just a few folk out there in faction-land, to strangle the life and soul out of the show, that's a real danger," Mr Rudd said.

"The membership of the ALP and the Australian labour movement must once again take control of the party and the movement."

Originally published as Julia tells - why I knifed Kevin Rudd