Nyron Nosworthy (centre) flanked by Mike Riley and Howard Webb.
Sunderland boss Roy Keane has found an unlikely ally in referee Howard Webb after his FA improper conduct charge.
Webb says he understands why managers get angry at referees' mistakes, but that they are only human.
Keane was charged following comments to Martin Atkinson during Saturday's defeat by Chelsea at Stamford Bridge.
Webb told BBC Radio Newcastle: "Passion is a big part of football. It hurts when we get things wrong, but there is also a line which can't be crossed."
Webb was speaking during a trip to Washington, in Tyne and Wear, where he took a coaching session with school-children. He was accompanied by Premier League colleague Mike Riley and Sunderland defender Nyron Nosworthy at a Barclays event for the Premier League's 'Get on with the Game' campaign.
Webb, who referees Arsenal against Manchester United this weekend, said: "We do not want to cut passion out of the game. It is what sets it apart from other sports for me. All we want to ask is that people realise there is a line that cannot be crossed.
I'd hate to think people feel we drive away from games happy with ourselves when we have made a mistake
"There has to be that little switch in the head which comes on and tells you 'that's enough'. It is down to respecting each other. But it is not just respect when things are going well, there has to be respect when mistakes are made as well. Any mistake made by a referee is not intentional."
Webb and Riley are among the senior figures on the Premier League list and both referee in Champions League and Uefa Cup matches as well. Webb will also be one of 38 referees officiating at the World Cup in South Africa in 2010.
He revealed he gets upset when he makes a mistake during a game and sees the evidence on screen afterwards. "It hurts when that happens," he said. "I will go home after a game where I have made a mistake and I will not be very pleased with myself.
"I will regularly look back at my performances and work out ways in which I could have done things better. I'd hate to think people feel we drive away from games happy with ourselves when we have made a mistake.
"We are only human after all but we want to be as accurate as we can be, as often as we can be."
Keane, meanwhile, claims he did not swear at Martin Atkinson after his side were left trailing 3-0 at half time, with the third goal a source of particular grievance to the Black Cats boss. Keane felt defender Pascal Chimbonda had been fouled by Chelsea's Joe Cole in the lead-up to Nicolas Anelka's second goal.
Keane said: "I asked the referee at half-time about what had happened. There was no swearing and I was not aggressive. He asked me not to come to the dug-out for the second half, so whether that means I was sent off I don't know. "
The answer came with the charge this week. Keane has until 19 November to respond to it but his disciplinary record as a manager and video evidence may help him argue his case in this one.
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