Around two hectares of woodland and scrubland has been damaged by a grass fire in Keston.
Four fire engines and over 20 firefighters from Orpington and Biggin Hill attended the scene on Saturday (March 30).
The brigade was called at 1.50pm and the fire was under control almost three hours later, at 4.48pm.
A brigade spokesman said: "As the weather hopefully begins to get a bit warmer we want people to enjoy the sun but we would also urge them to take a few simple precautions to help us prevent grass fires like this from starting.
"A small spark from a cigarette is often all it takes to start a grass fire in these dry conditions.
"It really is important that smokers dispose of their cigarettes properly.
"Drivers also need to take care not to throw cigarettes out of car windows as they can easily burn grass verges.
"If you see a grass fire, don't attempt to put it out yourself as grass fires can be fast moving and change direction without warning.
"Call the fire brigade and let us know where the fire is."
The cause of the incident is under investigation.
Did you see the fire? Do you have any pictures? Call the news room on 01689 885 711 or send an e-mail.