The killer of `` Harry Potter '' actor jailed for life , must serve at least 20 years . Score: 6 Knife crime in Britain is political hot topic due to spate of recent killings .
The killer of `` Harry Potter '' actor jailed for life , must serve at least 20 years . Karl Bishop , 22 , attacked Rob Knox with 2 knives in southeast London last May . Knife crime in Britain is political hot topic due to spate of recent killings .