They said the country faced a water, energy and food triple crisis through the drought and war in Ukraine.
Matt Williams, of the Energy and Climate Intelligence Unit, said: “Many families are already struggling to afford food without the impacts of dry weather.
“The country’s farmers fear some food production may fall by 50 per cent. Some crops that need wetter conditions, like oilseed rape, can’t be planted right now.
“Many farmers are expressing fears about bone-dry crops simply catching fire. They are already dealing with crippling costs for oil and gas used to heat glasshouses, make fertilisers, for vehicles and machines.
“Most chemical fertilisers currently cost at least twice what they did a year ago.”
The National Drought Group of decision-makers from Government, water companies and charities was told on Friday: “Irrigation options are diminishing with reservoirs being emptied fast.”
Losses of 10-50 per cent are expected for crops including carrots, onions, sugar beet, apples and hops.
Professor Michael Winter, of Exeter University, said: “The drought is certainly not helping UK food security.
“It is too soon to say what all this adds up to, but repeated summer seasons of higher temperatures and low rainfall could shift arable production westwards in the long term – an interesting prospect for West Country farmers.”
Some farmers have raided their winter food stock because the grass is too scorched for cows to graze.
And worldwide shipping woes that have sent prices of food, clothes and goods soaring has put further pressure on cash-strapped households and businesses.
Heath Zarin, founder of EV Cargo, which handles logistics and supply chains for Asda, Sainsbury’s and Next stores, said: “It’s going to take a period of years to stabilise and get back to normal.
“It’s very serious – and another reason why inflation and higher prices are likely to be with us for longer than we’d like.”