Convicted knife attackers are recording rap videos boasting of their crimes from behind bars and broadcasting them on Youtube in a bid to instruct associates to commit further violent crimes.
A Sunday Times investigation found a number of videos by convicted knife offenders promoting violence on the video-streaming service owned by Google.
In one, featuring inmates including a man who goes by the moniker P Wave who claims he is serving a six-year sentence, the rapper warns an unidentified enemy that he is planning to 'grab him' and 'stab him'.
In another video, a brute convicted of GBH with intent - the most serious violent crime shy of attempted murder - raps about killing and indiscriminate attacks.
The revelation comes after another bloody week in which six people were fatally stabbed across the UK.