A civil rights group has released a new smartphone 'stealth' app which allows users to record video of police encounters without the officer's knowledge. Called the 'Police Tape', the app makes the phone act as if it is off when recording video displaying a blank screen and when audio is being recorded, the app automatically minimises and disappears.

'Police often videotape civilians and civilians have a constitutionally protected right to videotape police,' said Alexander Shalom of the ACLU to the Star Ledger. 'When people know they're being watched, they tend to behave well.'

Last month the New York Civil Liverties Union launched a similar smartphone app called 'Stop and Frisk Watch' to counteract what it feels are controversial practices by the New York Police Department. The signature feature of the 'Police Tape' app is the instant uploading of any recorded content automatically to the ACLU server .