Researchers in Stanford have discovered that your phone call can be monitored by using their in build gyroscopes. The researchers along with a defence research group at Rafael have worked out a way to spy on smartphones using gyroscopes ad will be publishing their results under the catchy title 'Gyrophone: Recognizing Speech From Gyroscope Signals' study.

It appears that the gyroscopes integrated into smartphones were sensitive enough to enable some sound waves to be picked up, transforming them into crude microphones. Researchers noted: "We show that we can use gyroscopes to eavesdrop on speech without using the microphone at all, which can potentially risk private information such as identity, social security and credit card numbers.

"We show that the acoustic signal measured by the gyroscope can reveal private information about the phone's environment such as who is speaking in the room and, to some extent, what is being said. "We use signal processing and machine learning to analyse speech from very low frequency samples.

Once they do more work with low-frequency signal processing software, researchers claim it has to be possible to raise the quality of the information pulled out from the gyroscope."

The team achieved about 50 per cent success rate for speaker identification from a set of 10 speakers. It is still not there yet, but it could be what spooks of the future will be using to listen in on your calls.