Hoax calls made to the London Fire Brigade in Croydon have fallen by 72 percent since 2001.
Fire crews attended 472 malicious 999 calls in Croydon in 2001, but the figure had fallen to 131 last year.
The fire brigade have taken various measures to help cut hoax calls, including training 999 control officers to pro-actively challenge callers if they believe them to be making prank calls.
Other tactics include working with mobile phone operators, to identify repeated hoax or abusive calls. This has lead to around 100 mobile phones being cut off each year.
The Brigade have also launched youth programmes in the community, which provide opportunities for firefighters to explain to young people the consequences of hoax calls.
Chris Bigland, the Brigade's Borough Commander for Croydon said: "Hoax calls put lives at risk, are a waste of our firefighters valuable time and drain on the Brigade's resources.
"Every time our crews are sent out to investigate a prank call they are unavailable to attend genuine, potentially life threatening emergencies in the borough.
"We have taken a number of measures to root out hoax calls and now attend far fewer than before.
"But we’re not complacent and will continue to work to drive down the number of calls like this that we receive in Croydon."