Arsenal boss Arsene Wenger admits seeing his developed players quit for other clubs hurts the most.

The likes of Cesc Fabregas, Robin van Persie, Samir Nasri, Alex Song, Gael Clichy and Bacary Sagna all left between 2012-2014 and Wenger has since revealed that it was one of his toughest periods as Arsenal manager.

"That is what makes me saddest in football," he said. "Modern society has had a great revolution and a very positive one in knowledge but instability has become much more widespread, all over the world. And I think sport is one place where these values can be defended. It's important for the club. That is why leadership inside the club is so important."