Farmers across the country have urged members of the public to boycott plans to light dangerous sky lanterns in a show of solidarity for NHS workers.
The National Fire Chiefs Council (NFCC) also warned the campaign was "misguided".
"The NFCC believes the suggestion that people should set off highly flammable lanterns – at a time when wildfires are likely to be on the increase due to the weather conditions – should be highly discouraged," a spokesman said.
"This could lead to an intensive and complex large-scale incident; time which could be spent supporting vulnerable people in the community.
"Lanterns are a fire hazard; pose a risk to livestock, agriculture, thatched properties and hazardous material sites. Almost 90 local authorities across the UK have banned their use," he added.
In 2013, a fire in the West Midlands caused by a lantern took 39 fire appliances and more than 200 firefighters several days to tackle.
The National Farmers' Union said it had communicated its concerns to the company behind the drive - a London-based lantern manufacturer.
An NFU spokesman said: “Although this initiative may be well-intentioned and aims to raise money for the NHS, sky lanterns pose a serious fire risk and a danger to animals who may ingest the debris.
“The NFU has campaigned against their use as we have heard from dozens of farmers over many years about the gruesome injuries sky lanterns have caused to their livestock and other animals, as well as devastating fire damage on-farm to hay, straw and farm buildings. They also land as unnecessary litter wherever they fall.
We would also ask people to think about the heightened and unnecessary strain this will cause to our already stretched emergency services who need to focus on the national response to the coronavirus outbreak.
“We are in contact with the company to express our concerns about this well-intended but seriously concerning initiative and would encourage anyone that does wish to support our invaluable NHS to do so through established charitable routes.”
Campaign against sky lanterns
While many councils have already banned sky lanterns, recognising the danger they pose, the NFU would like to see a total ban across England and Wales to safeguard property and animals.
Already, more than 200 people have added their backing using the NFU's sky lanterns campaign tool just 24 hours after the plans to light lanterns for the NHS were announced.