People are being urged to take extra care to avoid causing countryside fires in hot weather, with some farmers saying they have lost crops worth thousands of pounds.
The National Farmers’ Union (NFU) said fires were one of the biggest risks facing farmers during heatwaves.
A farmer told the BBC he lost around £40,000 worth of crops when one of his fields went up in flames last week.
England has experienced its driest start to the year since 1976.
The hottest temperature on record in the UK was recorded last Tuesday, with thermometers reaching 40.3C in Lincolnshire and more than 30 locations reaching temperatures above the previous record.
David Exwood, vice-president of the NFU, said even as the weather turns cooler, the lack of rain has increased the risk of bushfires.
“There needs to be extreme caution when people are out in the countryside because anything can catch fire in this weather,” he said.
Andy Barr, who owns an 800-acre farm in Lenham, Kent, had 50 acres of barley destroyed by fire last Saturday.
Although he hopes to make an insurance claim, Barr said the crop was worth around £40,000.
He said it was a big shock to see his hard work go up in flames.
“You spend a year growing it and you really enjoy seeing the fruits of your labor at this time of year. So it was very disappointing,” he said.
“But I’ve gotten over the shock now and we’re just at the slightly worrying times to see what the insurers come up with.”
Barr was also grateful to the firefighters and neighbors who helped stop the fire from spreading by plowing crops that had not yet caught fire to create a firebreak.
Rural insurer NFU Mutual said the majority of farmers insured buildings, machinery and crops, and said it had seen a “significant increase” in farm fire claims during the heatwave in recent weeks.
Last year it estimated the cost of farm fire claims to be in excess of £70m.
It urged people not to drop used matches or cigarettes, not to use disposable barbecues on grass or bog and not to drop litter, as discarded bottles can focus sunlight and start a fire.
The NFU’s David Exwood said the dry, hot weather also led to reduced yields and quality of some crops such as potatoes, sugar beet and maize.
He said this could lead to a shortage of some products on store shelves in the short term and increased prices for customers.
The longer the dry weather continues, the greater the impact, he added.
On his own farm in Sussex, Exwood said his maize was struggling due to a lack of rain and he expected a “dramatically reduced yield”, which could cost him tens of thousands of pounds.
Hannah Buisman, who works on her parents’ farm near St Albans in Hertfordshire, said they had also seen reduced yields of hay and grain crops due to the heat.
She said this hit the farm financially, at a time when the cost of things like energy was going up.
Buisman said the family had also put off combining crops last week because they felt it was too dangerous in the hot weather. If combines hit a bottle left in a field or flint, it could hit a flame and cause a fire, she explained.
She urged people not to leave rubbish in the fields, adding that a neighboring farm had lost 240 acres of crops in a fire.
“It’s a worst nightmare, especially in years as volatile as these,” she said.