Prime Minister Malcolm Turnbull on ABC's 7.30 with Leigh Sales on Wednesday night. Mr Turnbull denied he was afflicted with insomnia, telling 7.30 viewers: "Ah, you know what? I sleep right through the night." He then asked Sales if she slept well. Her response? "No. I wake up often in the night, which is why I assume everybody does and I'm sure you don't sleep through every night." At this point, Mr Turnbull could have suggested Sales try a herbal remedy (St John's Wort), peppermint tea or a stiff drink before bed.

Leigh Sales asked Malcolm Turnbull why the major political parties didn't co-operate on other issues. Credit:ABC Instead, he told Sales she "would be amazed" by his dozing. "The key to being a happy and effective prime minister is to get a good night's sleep and plenty of exercise," Mr Turnbull said. It was an illuminating conclusion to an interview that began with Mr Turnbull almost tongue-tied and invoking the memory of the 1967 referendum recognising Indigenous people as full citizens. "I am so proud that this has occurred while I'm prime minister, while the Liberal and National parties are in government," he said.

Asked about the contribution of the Labor Party, Mr Turnbull said it was not the time to do the "usual tit-for-tat" before doing exactly that. "Labor certainly supported it and that's good," he said. "They had six years in office and did nothing about it and that's not so good. "And of course, they did everything they could to stop every Australian having their say and that was really bad." After promising to "whip through some other issues", Sales asked Mr Turnbull about his handling of the citizenship saga, and why he did not refer every politician "under a cloud" to the High Court. After Sales threw shade on his answers, Mr Turnbull accused the ABC of a "conspicuous failure" when it came to covering the admittedly complex issue of citizenship.

Sales' next question had a nautical theme, asking her sparring partner what barnacles were left on the ship of state. He ticked off energy policy and same-sex marriage as successfully removed from the government's hull before returning to second and third passports. Mr Turnbull said his government had dealt with citizenship with "full transparency". "Labor is the one that is running, you know, the protection racket on some of its MPs." Sales then sought to compare the Coalition unfavourably to Labor. "When voters look at the Coalition, they see disunity, they see you consistently behind in the polls, they see some members of your team sniping at you. Why?" she said. With words echoing Taylor Swift, Mr Turnbull told Sales to ask "the snipers why they snipe".

Listing his government's achievements, Mr Turnbull said: "It's a very, very long list of achievements we have got done despite our many failings, which you remind me of from time to time." But Mr Turnbull was having none of Sales' suggestion that his government might be engaging in a spot of petty theft of Labor policies. "Is the common thread of your prime ministership not ideology or conviction but survival?" Sales asked. Turnbull's response: "It is delivery and it is conviction and the conviction that we must deliver strong economic growth" and so on. After a tug-of-war over who owns David Gonski ("Labor does not believe in what David Gonski proposed"), Sales and Mr Turnbull shared their sleep habits and wished each other a happy Christmas.