Millions of people in the United Kingdom have been warned not to light anything that could spark a wildfire, including barbecues and garden incinerators, in "the most extensive use" of the country's mobile phone alert system.

The government sent the emergency alert on Friday evening, which began appearing on mobile devices from 7 pm (1800 GMT).

Prime Minister Andy Burnham has told members of the public to take the warning "seriously," and said it was triggered at the request of firefighters.

Burnham had earlier visited Stourbridge in the West Midlands, where a wildfire destroyed 19 homes on Thursday, the hottest day of the year so far.

The Stourbridge blaze spread across more than 500 acres, with the West Midlands Fire Service summoned to "hundreds and hundreds of incidents" throughout its patch, according to the area's chief fire officer Simon Tuhill.

Friday is provisionally a record-breaking 10th day in 2026 where temperatures have exceeded 35 degrees Celsius or more, according to the Met Office.

Frittenden, near Ashford in Kent, was among the hottest places, where temperatures reached 35.3 degrees.

In the West Midlands, Burnham described Britain as "a tinderbox right now" with "37 fires smouldering around the country."

In South Wales, around 100 military personnel from the Queen's Own Gurkha Logistic Regiment, supported by the 22 Engineer Regiment, have been deployed to support rescue and recovery efforts.

Among their equipment are four water bowsers, each capable of storing and transporting 20,000 litres of water.

A further 100 members of the Armed Forces set to be deployed on Friday evening.

The message which appeared on mobile devices was "the most extensive use of the UK's emergency alert system in response to an active incident," Cabinet Office minister Louise Haigh, the first secretary of state, said.

She said the decision to send the alert "reflects the seriousness with which the government is acting to safeguard people and property."

Haigh continued: "During this period of extreme heat, we are asking people to take simple steps to limit the risk of further fires."

"By following the safety guidance, everyone can play their part in protecting local communities and supporting our frontline services who are working around the clock to keep people safe."

"The government will continue to provide every assistance to communities being impacted by these fires, including the deployment of 100 additional military personnel in major incident areas."

Angela Rayner, the communities secretary, said: "As well as supporting firefighters on the ground now, my department will hold a summit bringing together fire chiefs, the National Fire Chiefs' Council, the Fire Brigades Union and other key organizations to look at our future response."

"To the residents affected, particularly those who lost their homes and their life's possessions to fire – we will work with the mayor and local leaders to make sure you are supported."

The alert read: "There is a very high risk of wildfires nationally."

"Residents, landowners and visitors should not undertake any activity that could start a fire, including disposable barbecues, firepits, garden incinerators or fireworks."

"Even a small flame can rapidly develop into a major wildfire placing lives, homes, businesses and emergency responders at risk."

Burnham wrote on X: "This evening, an emergency alert has been sent to people across England and Wales as the wildfire risk remains very high. The request came directly from fire and rescue services."

"I was in Stourbridge today and saw first-hand the devastating impact these fires have had on people's homes and lives."

"Our priority now is to keep everyone safe and prevent more fires from starting."

"During this period of extreme heat, I'm asking everyone to take extra care. Please do not light any fires in gardens, the countryside or other open spaces, including parks, moorland and wooded areas."

"Our firefighters and emergency responders are working around the clock in incredibly difficult conditions."

"We can all help them. Please take the emergency alert seriously and follow the guidance in place."

The prime minister earlier announced a ban on disposable barbecues in England, Wales and Scotland has come into force "until further notice."

He said: "The temporary ban on barbecues, disposable barbecues, comes in today."

"All retailers will be receiving notification of that ban, and we ask them to, obviously, implement it in full until further notice when we can remove it."

Aerial firefighting support, such as aeroplanes and helicopters similar to those used to fight fires in Suffolk and the Isle of Wight earlier this summer, will be "commissioned nationally."

Heat health alerts from the UK Health Security Agency (UKHSA) are in place until 10 am on Saturday across London, the South East, the South West, the East of England, the East Midlands and the West Midlands.