Manchester United boss Sir Alex Ferguson admits he fears one day being attacked in the dugout by a fan.

"I think you need to look at the nature of supporters to understand it [abuse] is an issue and why security has to be absolutely 100 per cent," Ferguson said. "You can't have situations where supporters lean over the dugout and round corners and spit. That has happened in the past but nowadays it's too dangerous.

"The verbal stuff is not a problem. You just worry if some idiot does go a step further. That's your problem."