He wrote:

(Abbott) personifies the political problems of the Democrats. While he can win support from students because of the shocking state of affairs in AUS, he cannot take the next step and take control himself because of his conservative moral views. Abbott is opposed to any legalisation of homosexuality... the students may be more conservative than they were a few years ago, but they have not swung back to the right as much as that.

Fast-forward to the present day – through decades of personal and political drama between the two future prime ministers – and Turnbull, now 62, continues to critique the conservatism of Tony Abbott, now 59.

On Monday evening, at a centre-right UK think tank, Turnbull spoke about how the founder of the modern Liberal party Sir Robert Menzies went to "great pains" not call the party "conservative".

Conservative media commentators have lashed Turnbull for the speech, suggesting the prime minister is provoking the more conservative MPs within his party.

Last month, former prime minister and now backbencher Tony Abbott came up with his own conservative "manifesto" for the government, differentiating himself from the Turnbull government's policies.

Abbott, who was unseated as prime minister by Turnbull in 2015, has also committed to stay around in politics, telling his supporters within the party who are upset with Turnbull that "we need strong, liberal, conservative voices now more than ever".