And Opposition Leader Kevin Rudd has increased his lead as preferred prime minister. He is up one point to 44 per cent, while Mr Howard has dropped one point to 39 per cent. The bad polls come as the Government waits on tenterhooks to see whether interest rates rise tomorrow, which could further damage its standing.

Speaking in response to the internal report, Mr Howard said Labor had been running "flat out" on the issue of his age, so eventually some people would pick that up. The extraordinary leak of highly confidential material has unnerved the Liberal Party, which now fears for the security of future research. The report went to federal director Brian Loughnane, who is conducting an investigation into the leak, and a couple of others in the federal secretariat. Mr Howard did not have a hard copy. Mr Textor gave Powerpoint presentations to senior federal and state party figures.

The Crosby/Textor report, prepared in late June, strongly highlighted voters' perception of the younger, attractive Mr Rudd, who represented the opportunity for generational change. They saw Mr Rudd as strong and competent, "so just like John Howard, but younger", and were disillusioned with the Liberals' dishonesty and broken promises.

The Labor leader will today move to capitalise his appeal to younger voters when he unveils a US-style campaign website, "kevin07". Mr Howard's ministers yesterday leapt to his defence. Senate leader Nick Minchin said he said he was "one of the most honest, straightforward politicians" Australia had had.

Senate deputy leader Helen Coonan said Mr Howard "is certainly someone who seems to me to be on top of his game". The Costello forces quickly moved to head off any suggestion of pressure for a leadership change. Minister for Ageing Chris Pyne, a confidant of the Treasurer, said: "There's absolutely no suggestion of any such change before the election".

The blow to Mr Howard comes only weeks after a new biography of him stirred leadership talk when it reported trenchant criticisms from Treasurer Peter Costello. Meanwhile, Mr Howard's first biographer, David Barnett, has said the Prime Minister should step aside. Writing in The Canberra Times, he said Mr Howard had "failed to turn around the catastrophic collapse of support for the Coalition that has occurred since Rudd became ALP leader last year".

Mr Rudd said the internal report, which advocated that the Government attack the states, showed Mr Howard was poll-driven. He also started to pressure Mr Howard over the election date, saying if he delayed until November it would be a sign he was "desperate". Crosby/Textor's internal report said: "Kevin Rudd is someone voters appear willing — at this early stage — to make a long-term investment in, particularly for young voters … The idea of generational change is now attractive where it wasn't previously because Rudd, unlike (Kim) Beazley, (Mark) Latham and (Simon) Crean, looks energetic and enthusiastic."

Mr Howard was being seen as "increasingly rattled and not responding well under pressure". "With the arrival of a younger leadership alternative, the age and energy of the Government has also been thrown into question, rasing questions about whether they are listening or getting arrogant, complacent and reactive," it said. "Rudd's ability to to remain unfazed is a contrast not only against Beazley and Latham … but as voters have seen more recently, Rudd is politically competent and strong and able to match and even rattle John Howard."