The Prime Minister returned to the political fray in ebullient mood after his summer holidays, brushing off speculation about a possible leadership challenge by Foreign Secretary David Miliband.

He said that ministers were working on a package of measures, to be unveiled in September, to help families struggling with rising fuel bills and mortgage repayments.

As he headed off for the final days of the Olympics in Beijing, Mr Brown, told reporters: "We are getting on with the job.

"Look, what the people of Britain are concerned about is what is happening to their gas and electricity bills, what is happening to the oil price and the petrol price at the pumps.

"These are the issues that they want us to deal with. You will see us dealing with some of these issues as we come back in September."

The Prime Minister dismissed suggestions that Mr Miliband was preparing a leadership bid in the wake of the Foreign Secretary's article in The Guardian last month setting out his vision to revive Labour fortunes.

"We have been working pretty closely together on Georgia and issues related to Afghanistan," he said.

"The article he wrote in The Guardian was an article that any member of the Cabinet could have written or I could have written. These are debates that all members of the Cabinet have got to be involved in."

Pressed on his relations with Mr Miliband, he replied simply: "Fine."