Four fire engines and around 25 firefighters tackled a fire in a field on Charmwood Lane in Orpington.
Around four hectares of straw was alight, with crews making steady progress through the afternoon to extinguish the fire.
Firefighters were supported at the scene by the Brigade's All-Wheel Drive (AWD) vehicle.
Permanently introduced earlier this year, the AWD vehicle, which is based at Biggin Hill Fire Station, can do many of the same tasks as a standard appliance, such as pump water with a capacity of around 1,000 litres.
The vehicle's four-wheel drive capability also means it is easier to reach incidents in more remote locations than standard fire appliances, helping to support the Brigade all-year round, including at grass fires.
All firefighters have received enhanced training for grass fires and wildfires and a Wildfire Support Officer was also in attendance. They were deployed as a wildfire tactical advisor, providing key support to the Incident Commander. The welfare of operational crews working in hot weather conditions is a key priority and firefighters are provided with additional hydration packs, sun cream and protective headwear for personal protection on the incident ground.
London Fire Brigade is also trialling new wildfire response vehicles this summer, which have off-road capabilities and technology that allows firefighters to pump water while driving, enabling them to tackle an outdoor fire more quickly and safely.
Today's fire comes as London experiences temperatures of over 30 degrees Celcius with a yellow Heat Health alert issued by the UK Health Security Agency. During this type of weather, the risk of grass fires increases and the Brigade is asking the public to follow crucial safety advice that will help protect themselves, others, the environment and their property.
London Fire Brigade Assistant Commissioner for Prevention and Protection, Craig Carter, said: "We know many Londoners will want to enjoy the nice weather by visiting a park or open space. However, we’re asking people not to take disposable barbecues with them as they can cause grass fires, especially in hot weather when the ground is dry. These fires are unpredictable and can spread rapidly, causing a significant amount of damage.
"Don’t be tempted to barbecue on your balcony either. Balconies can contain combustible materials which can pose a risk to those barbecuing and others living nearby.
"If you are having a barbecue, never leave it unattended and be careful where it’s positioned. Aim for level ground and keep barbecues well away from anything flammable like sheds, fences, trees or tents."
As well as disposable barbecues, discarded smoking materials and leftover rubbish also pose a huge fire risk. People are asked to ensure their rubbish is placed securely inside a bin or to take it home with them. If you have had a cigarette, please make sure that it is completely out.
The Brigade was called to the fire in Orpington at 1223 and the fire was extinguished by 1545. Crews from Orpington, Bromley, Sidcup and Biggin Hill fire stations have been at the scene.