Pressure from US lawmakers has convinced Microsoft and Google to add a kill switch to their smartphone operating systems in a move to deter the larcenous.

The pressure came from "Secure our Smartphones" (SOS), an organization set up by New York Attorney General Eric Schneiderman and San Francisco District Attorney George Gascón, who were concerned about rampant smartphone theft in their cities.

The group had already convinced Apple to add the technology to iOS, but now such systems will be installed on 97 per cent of the smartphones in the US following the announcement.

"The commitments of Google and Microsoft are giant steps toward consumer safety and the statistics released today illustrate the stunning effectiveness of kill switches," said Schneiderman in a statement.

"In just one year, the Secure Our Smartphones Initiative has made tremendous strides towards curtailing the alarming trend of violent smartphone theft," Schneiderman said. "We will continue the fight to ensure that companies put consumers' safety first and work toward ending the epidemic of smartphone theft. "

Based on a report SOS released on Thursday, the technology has been highly effective at stopping phone thefts, which have grown to epidemic proportions in some cities. Data collected from the New York police department shows that since Apple's introduction of Activation Lock for iOS in September, the number of iPhone robberies has fallen dramatically.

In the first five months of this year, robberies and grand larcenies involving Apple hardware fell by 19 per cent and 29 per cent respectively compared to the year before. By contrast, robberies involving Samsung phones running Android increased by 40 per cent, indicating thieves are now shunning iOS devices in favor of easier-to-fence kit.

Over the same period in San Francisco, iPhone robberies declined 38 per cent while those involving Samsung hardware rose by 12 per cent. In London, iPhone thefts were down 24 per cent, and Samsung saw a 3 per cent rise in its customers' losses.

"We can make the violent epidemic of smartphone theft a thing of the past, and these numbers prove that," said San Francisco's Gascón.

"It was evident from day one that a technological solution was not only possible, but that it would serve as an effective deterrent to this growing threat," he said. "In the year ahead we will work to ensure this technology is deployed industry-wide, and in the most effective manner possible."

Not that some in the industry are particularly keen on the idea. The CTIA, which dubs itself "the Wireless Association", fought long and hard against mandatory installation of kill switches. SOS claims this is because the industry doesn't want to lose out on lucrative phone-insurance packages, but CTIA has now said it will install the technology by July next year.

Microsoft and Google are expected to beat that deadline handily with their new code. Microsoft VP of government affairs Fred Humphries said in a blog post that Microsoft would move quickly to add remote kill and wipe code to Windows Phone 8.0 systems and above. ®