Neil Back on Wednesday launched a robust defence of England captain Martin Johnson, insisting that he should not receive further punishment for the infamous punch which felled Saracens hooker Robbie Russell.

Johnson, who was yellow-carded for the upper-cut which left Russell with blood pouring from an eye wound in Leicester's televised Premiership match at Vicarage Road on Saturday, faces a potential disrepute charge which could keep him out of a vital part of the Six Nations championship.

He has admitted he was wrong, regrets throwing the haymaker and Leicester team-mate Back hopes his contrition will save him from a ban.

"Jonno has said he was wrong to do what he did, but at the time I don't think he was aware of what was happening behind him," said Back (pictured) as he prepared for England's clash against Ireland at Twickenham on Saturday.

"He didn't know who it was or what he was up to, so he defended himself and just caught him with a punch.

"There's no room for that in the game. He's put his hand up, he shouldn't have done it and hopefully that's the end of it."

Back insists Johnson, despite a string of disciplinary skirmishes in the past, most notably when he felled All Black Justin Marshall in 1997 and then was banned for five weeks for kneeing and stamping on Saracens fly-half Duncan McRae in December 2000, is no thug.

"It's a very physical game," said Back. "When things flare up, the immediate reaction of any person is to defend themselves and that's all that Jonno was doing.

"He's not a player who purposefully goes out on the pitch to be violent and cause damage to any other players other than in the true spirit of the game.

"The pressure is the same for any player when they go on the pitch with the kids and everybody else watching. You've got a duty to be on your best behaviour, but we've all been in those situations where things flare up.

"If he had missed with that punch or if it hadn't connected so well, in the words of Bill McLaren 'there would have been a fisticuffs' and that would have been the end of it. Just because blood was drawn it looked more malicious than it actually was.

"Jonno is a great captain, a great leader and a great player and people respect him for that."

Back admitted he thought the Irish might try to cash in on Johnson's latest escapade by trying to intimidate him on Saturday.

"They might try to niggle him," said Back. "But, if they do, that will just play into our hands. The more attention they give Jonno the more space the rest of the lads will enjoy."