The food industry is “on notice” that a sugar tax is still on the table unless tactics change to tackle the obesity crisis, the chief medical officer for England has warned.

Prof Sally Davies said large food companies needed to make significant changes in their manufacturing and marketing strategies if they did not want to see a sugar tax imposed, after her annual report said obesity should be treated as a priority for the government.

The report does not mention the possibility of a sugar tax, although it notes that product labelling and placement can influence shoppers’ behaviour, but Davies said on Friday the government should impose a tax if the industry did not respond to the crisis warnings.

“I think [sugar tax] is a runner,” she told the BBC’s Radio 4 Today programme. “With smoking, it took 20 years for the public to believe [a tax] was needed. I think we’re at a tipping point. I think industry is on notice. If it doesn’t deliver, then we’ll have to look at a sugar tax.

“Industry could solve this without a tax on sugary drink, so if they do we won’t need it. We’ll only need it if industry don’t reformulate, resize, sort their advertising out, make healthy life an easy option.”

David Cameron has consistently ruled out a sugar tax, but the cross-party health select committee, chaired by the Conservative MP Dr Sarah Wollaston, strongly endorses a 20% levy. Jamie Oliver, who gave evidence to the committee, has also campaigned for a sugar tax.

The CMO’s annual report for 2014, which focuses on women’s health, said the government should include obesity in its national risk register of civil emergencies, which includes terror attacks, natural disasters and disease outbreaks as crises for which the country needs to prepare.

In 2013, more than half of women aged 34-44 and almost two-thirds of women aged 45-54 were classified as overweight or obese, the report found.

Davies said she was not directly likening obesity to terrorism but said elevating the problem to the risk register was a way to get the government to tackle the crisis at every level, rather than treating it solely as a health issue.

“Politicians have to know the public will be with them, and as with seat belts as well, attitudes can change,” she said. “Supermarkets have to stop cheap promotions on unhealthy food, putting it at the checkout. We have to limit advertising dramatically and particularly to children. One can of coke is more free sugar than an adolescent should have in a day.”

Davies said she believed attitudes were shifting. “I think we are getting somewhere, we’ve got polling data that shows the public see obesity as a major risk and the government has to do something about,” she said. “That is major movement on two or three years ago. We are seeing the impact of being overweight and obesity on their lives, it shortens lives.”