When Tony Abbott lost the University of Sydney Students' Representative Council presidency, he allegedly approached the woman who beat him and, leaning into her face, punched the wall on each side of her head.

Barbara Ramjan, a social work student in 1977, told the author and journalist David Marr she thought Mr Abbott was coming over to congratulate her. ''But no … he came up to within an inch of my nose and punched the wall on either side of my head. It was done to intimidate,'' she said.

The allegation is raised in Marr's article, Political Animal: The Making of Tony Abbott, in the latest issue of Quarterly Essay.

Tony Abbott's response ... "It never happened".

For a political leader still struggling to gain traction with female voters, it is a hugely damaging allegation and perhaps unsurprisingly Mr Abbott's rebuttal was the only comment he was prepared to make when he granted Marr an interview for the article.

''Our talk was off the record. Why? God knows. The one statement he insists I put his name to is this: he can't remember threatening Barbara Ramjan all those years ago at university and believes to have thrown those punches would be out of character,'' Marr wrote.

Yesterday Mr Abbott contacted the Herald with an on-the-record quote: ''It never happened."

Marr's previous foray into long form journalism in the Quarterly Essay was his June 2010 article, Power Trip: The Political Journey of Kevin Rudd, in which he skewered the then prime minister's ''angry heart'' on the eve of moves by his Labor colleagues to oust him from the leadership.

In his latest work, with Mr Abbott poised in opinion polls to capture the prime ministership, Marr charts his rise from university politics tyro through a learning curve of political fixer to Parliament and eventually the opposition leadership.

Marr traced the influences on Mr Abbott, including two Jesuits - one at Riverview and the other in England during his Rhodes scholarship days - John Howard and the ALP wrecking ball Bob Santamaria.

Marr said the Santamaria dictum - when you have not got the numbers be vicious - had become Mr Abbott's hallmark and, time and again, he had shown when there was a choice between values or politics he chose the pragmatic option.

''The joke goes that Abbott would be the first DLP prime minister of Australia,'' Marr said.

''He wouldn't mind us believing that … Ever since he stepped into Parliament nearly 20 years ago he has been invoking God and the Catholic values that drive him …

''How much would they drive Tony Abbott, PM? Which Abbott are we going to get when things are tough, I ask him: Values Abbott or Politics Abbott? I wish I could quote his answer. My sense is we'll get the Abbott he decides to give us at any particular time.''

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