With almost two in three Australian adults being overweight or obese and a quarter of all children also struggling with weight, TV chef Jamie Oliver has called on Malcolm Turnbull to do more.

Speaking exclusively to Fairfax Media, the 43-year-old said a sugar tax was sure to happen in the near future in Australia and described the PM as “laggard” on his approach to obesity.

“The sugary drinks tax is categorically the future,” Oliver told the publication. “Why would you not fight for child health? How can you call yourself a great leader if you don’t?”

Oliver said it was up to politicians, MPs, leaders and CEOs to step up and take action now and warned that he would be getting personal until a change occurs.

“I’ll pat you on the back if you do right and if you don’t we’re going to absolutely make a campaign of making you held to account,” he said.

A sugar tax is already working in the United Kingdom, with the government announcing a strict new diet for the nation. It came following suggestions that the British public had become too fat.

Read more: UK told they’re too fat and put on strict health diet

Citizens are being told they must try to restrict their daily food intake to a meagre 400 calories for breakfast and 600 calories at lunch and dinner time, while Public Health England said it had no choice but to roll out the extreme rules because Brits are continually consuming more than the recommended number of calories and food.

Items sold at take away restaurants and meals available at convenience stores have also been targeted in the crackdown, with food suppliers forced to reduce the level of calories in pre-packaged meals and snacks.

In Australia, the Australian Medical Association’s call for a sugar tax on unhealthy beverages was recently declined by the government, although it is continuing to campaign for a tax. Australian Beverages Council (ABC) recently announced it would reduce its sugar use by 20 per cent by 2025, although AMA president Dr Tony Bartone said it was inadequate.

Read more: Here’s what the sugar tax would do to prices

“The soft drink industry’s commitment to cut sugar content is too little over too long a period, and there is no guarantee of less sugar in the most popular sugar sweetened beverages (SSBs),” Dr Bartone said. “By the time 2025 rolls around, more Australians will be affected by the health harms of obesity, including from the high sugar content in SSBs.”

Like Oliver, Bartone said the best way to achieve change is with a sugar tax.

“We have seen success with excise increases on tobacco products. And we are seeing early successes with sugar taxes in Mexico and some American States,” Bartone said. “The AMA strongly supports the introduction of a sugar tax in Australia as part of a broad range of policies to combat obesity and improve the health of the population across all age groups.”

What do you think? Should Malcolm Turnbull introduce a sugar tax as a way of fighting obesity?