Sex offenders will be kept under surveillance by satellites and tested with lie detectors under new Government plans.The Home Secretary wants to use satellite-tracking for prisoners released on licence and offenders given community sentences.David Blunkett also wants to expand a new database which allows officers to share information on violent and sex offenders. And he plans to allow police and probation services them to use lie detectors to make sure sex offenders are keeping to the conditions of their release. Mr Blunkett told Sky News that satellite-tracking would be "a great safeguard, not just for sex offenders but for those...