When the British Government transferred sovereignty back to China 25 years ago, it promised to protect freedom of speech, but new laws have effectively silenced all criticism. Street protests have all but stopped, pro-democracy law-makers have been replaced by Beijing loyalists and Hong Kong's new Chief Executive is its former Security Chief, who led the crackdown. Danny Vincent follows the young journalists and activists who have lived through the street protest movement, as a result of which many are now in prison