About a fifth of the fresh food the UK imports comes from areas threatened with climate chaos, putting people’s health and diets at risk, MPs have found.

The environmental audit committee called on ministers to set out a clear plan for how the UK’s food supplies could be protected from the climate emergency and to publish information on how food may be affected by Brexit.

Currently, 40% of the UK’s food is imported, according to the report published on Tuesday. In the very near future, people would be at risk from sudden lurches in food prices if a no-deal Brexit resulted in trouble with imports, including higher costs, delays and shortages.

Mary Creagh, the chair of the committee, said: “We are facing a food security crisis, exacerbated by uncertainty over the UK’s future trading position with the EU and the rest of the world. Ministers must now publish all the information they hold from Operation Yellowhammer on food security and likely costs in the event of a no-deal Brexit.”

Beyond the immediate effects of Brexit, the climate emergency and changing trade relationships may put the British diet in jeopardy. The MPs called for a national food council that would cover food production, nutrition and public health issues, and for stringent annual targets to reduce the UK’s high levels of food waste.

Water consumption across the UK should be set at 100 litres (22 gallons) per person per day, the MPs found. This would require changes to water availability and potentially to metering. Sustainable cities should also be made more resilient to the effects of the climate crisis, and town planners should be more involved in improving the design of cities to reduce greenhouse gas emissions, for instance through more efficient transport networks.

The MPs also called for Public Health England to take on responsibility for adapting to the effects of the climate emergency – particularly through examining any measures needed to counter the spread, made easier by global heating, of emerging diseases such as Lyme disease, the incidence of which is rising.

Already, “unprecedented” damage has been done to natural systems around the world, from water and clean air to a stable climate and flourishing nature, the MPs said. The chancellor, Sajid Javid, has unveiled plans for a new Treasury study on the economics of biodiversity, to be led by Sir Partha Dasgupta and Sir David Attenborough.

A spokesperson for the Department for Environment, Food and Rural Affairs said: “We recognise the threat climate change poses to many facets of our national life, including our food production and supply, which is why the UK is the first major economy to legislate for net zero emissions by 2050.

“We already have a highly resilient food supply chain in the UK, and our national food strategy review is considering how we can further address the challenges of a changing climate and continue to deliver safe, healthy, affordable food now and for generations to come.”

Vicki Hird, a farming campaigner at the Sustain civil society organisation, said: “The MPs are spot on with this report, given the climate emergency and size of the challenge.

“For far too long we’ve left our vital food supply to be dominated by complex global supply chains and the junk food industry. We now have a highly vulnerable, unsustainable and inefficient food system that needs to be repaired using all the tools available. A [government] champion putting this all together coherently would be handy.”

She called for the government’s agriculture bill and environment bill to be brought back before parliament as a matter of urgency. “[We need] good farmers to be paid to produce more diverse and better food and to reduce reliance on vulnerable overseas suppliers,” Hird said.