Smartphone thefts in three major cities have dropped significantly since the implementation of the Activation Lock according to a recent study.

The Activation Lock, aka kill switch, is a safety mechanism that can render a smartphone useless after being stolen.

The number of iPhone thefts dropped by 50 percent in London, 40 percent in San Francisco and 25 percent in New York in the 12 months after Apple added the kill switch to its devices in September 2013 that allows the phones to be turned off remotely if they are stolen, Reuters reported.

"We have made real progress in tackling the smartphone theft epidemic that was affecting many major cities just two years ago," London Mayor Boris Johnson said, according to Reuters.

Numerous officials, including Johnson, San Francisco District Attorney George Gascon and New York state Attorney General Eric Schneiderman argued for new laws mandating kill switches.

Although a law mandating the Activation Lock has not gone into effect yet in California, Gascon said smartphone theft is dropping because some smartphone manufacturers have already started installing the software-based switches on the devices they sell.

"The wireless industry continues to roll out sophisticated new features, but preventing their own customers from being the target of a violent crime is the coolest technology they can bring to market," Gascon said, according to Reuters.

The Activation Lock, or Kill Switch, requires a user "to authorize a wipe or fresh install using the existing iCloud credentials on record, ensuring that a thief can't go ahead and just wipe the device easily to use it themselves or prepare it for sale on the secondary market," Tech Crunch reported.

Handheld devices were stolen from 1.6 million Americans in 2012, according to the National Consumers League. In California, smartphone theft accounts for more than half of all crimes in San Francisco, Oakland and other cities.

Apple, Samsung and Google have implemented kill switches on their iPhones and Androids. Microsoft is expected to incorporate a kill switch into its smartphone version of Windows 10.