Rishi Sunak’s plan to improve the UK’s food security will not help build farmer’s confidence in the short-term, the head of the country’s biggest farming body has said.

Food production was likely to drop next year, said Tom Bradshaw, the president of the National Farmers’ Union, who warned that the prime minister’s plan, published during the UK’s second annual Farm to Fork summit, failed to give farmers the solutions they needed.

On Tuesday, 70 food and farming businesses met at No 10 to discuss how to improve food security, as the government unveiled a plan to boost food production and security. The plan focused particularly on fruit and vegetables, the two food types most reliant on imports from abroad.

The new policies include changing planning laws to make it easier to build greenhouses and a replacement for the EU horticulture resilience scheme that would double the funding available to £80m a year.

In a briefing after the summit, Bradshaw said overall the changes would do little to fix the short-term challenges farmers currently faced.

He said: “I think that what’s missing from today, really. Today was more about the strategic long-term plan, it’s not about putting the building blocks in place that rebuild that confidence immediately.”

Last month, an annual survey by the NFU found farmers’ confidence was at its lowest since the first survey of its kind in 2010, which followed a winter of extreme weather when many farms flooded and farmers were unable to plant crops. There are also widespread concerns about the impact phasing out the EU’s basic payment scheme subsidies will have on farmers.

Bradshaw was keen to stress the importance of the Farm to Fork summit and said it marked a change from previous governments when it came to the importance of farming. However, he said: “I believe as we go into next year, we will have less food, [a] lower food security index than now.”

“I think that the government needs to take critical steps to get the industry on to a firmer footing, and willing to start that investment cycle. If they’re not doing that, then an industry that is not investing is not preparing for the future.”

The government has published its first ever food security index, which uses official data to paint a picture of Britain’s overall ability to produce enough food for its population.

The table revealed that the UK only produced 17% of its own fruit, and 55% of its own vegetables. Lamb and milk were the most secure foods, with producers respectively generating 7% and 5% more than the country needs.

Bradshaw welcomed the index but called on the government to begin setting food security targets for different food types. Other sector figures, however, cautioned that the index was based on old data.

Tom Lancaster, a land analyst at the Energy and Climate Intelligence Unit, said: “In only running to 2022, the new food security index is lagging behind the impacts of extreme weather and climate change that we’ve seen in the last 18 months.

“To address this, they could have done some interim analysis or even provided some interim commentary, but clearly chose not to.”

The index also outlined the main risks to future food security but the government was widely criticised for listing climate change as a “longer-term risk”.

Dustin Benton, the policy director at the Green Alliance, said: “The past 12 months have been 0.7C higher than the 1990-2020 average. Higher temperatures are associated with the sorts of extreme weather that cuts food production. Climate risks are no longer just a long-term problem.”

Rob Percival, the head of food policy at the Soil Association, said: “Absurdly, climate change is described as a ‘longer-term’ risk, despite the steady ratcheting of climate extremes and the profound effects already being felt on the ground.”

Steve Barclay, the environment secretary, said: “Today’s announcements will turbocharge the growth of our horticultural sector, supporting the building of cutting-edge glasshouses and innovative farming techniques to put British fruit and vegetables on our plates all-year round.

“We will continue to invest in and support farmers to produce the best of British food to strengthen our food security, championing innovation in the sector.”