Its gold again, the triple triple usain bolt is to hand back one of his olympic gold medals because a team mate tested positive for a banned substance. And the woman in charge of British Vogue is to step down after 25 years at the heart of the fashion industry. And coming up in sportsday on bbc news, Will Liverpool make it to their second wembley final in two years . Theyre playing southampton in the second leg of the league cup semifinal. Good evening. We start tonight with a Special Report on the marked increase in knife crime. An investigation for Bbc News At Ten has found that, last year, a knife or blade was used in a crime every 16 minutes somewhere in the uk. The number of incidents involving machetes has risen by over 60 in the past the years. The information was provided by Police Forces in england and wales. And records show there were at least 2,300 victims of knife crime last year aged 18 or younger, a rise of 45 over three years in england and wales. Our special correspond