England hooker Dylan Hartley could be hit with the second significant ban of his professional playing career.
The 25-year-old Northampton captain, who has made 39 Test match appearances, was last night cited for allegedly biting the finger of an opponent.
Hartley, who could land a maximum ban of four years, will face a disciplinary hearing possibly on Thursday following the first-half incident during last Saturday's RBS 6 Nations game against Ireland at Twickenham.
Six Nations organisers announced that Northampton forward Hartley had been reported by match commissioner Alberto Recaldini.
It is understood that Hartley is alleged to have bitten the finger of Ireland flanker Stephen Ferris.
A biting offence carries a low end entry point of a 12-week suspension, with 18 weeks for mid-range and 24-plus weeks at the top end in the International Rugby Board's disciplinary sanctions table.
The maximum sanction is a four-year punishment.
New Zealand-born Hartley served a 26-week ban for gouging in 2007 after being cited for making contact with the eye areas of three Wasps players - Jonny O'Connor, James Haskell and Joe Worsley - during a Premiership game.
He pleaded not guilty on all three counts, but a Rugby Football Union disciplinary panel found him guilty in relation to the Haskell and O'Connor incidents. He was cleared on the Worsley charge.
If Hartley is banned for his latest alleged transgression, he could easily be ruled out of England's three-Test tour to South Africa in June.
The RFU said: "The England management have been formally notified about the citing of Dylan Hartley and will not be making any comment until the resolution of the disciplinary hearing."
The match referee, Welshman Nigel Owens, did not see the alleged incident.
Owens, though, confirmed to the two captains - England's Chris Robshaw and Ireland's Rory Best - that it would be looked into after the match.
When Owens addressed Robshaw and Best on the pitch he said: "I have an accusation of biting, a clear mark on the finger.
"I did not see something. If I do it will be dealt with severely, which would be a red card.
"It could be dealt with afterwards. If it is seen it will be dealt with. I did not see it.
"Have a word. Nothing like that takes place in this game. I can only deal with what I see. Have a word please.
"I have had a look. Unless I can see it, it's been dealt with, okay?"
As the two forward packs then set themselves for a scrum, Owens added: "This game is difficult enough without stuff like that, is that clear?"
Owens then approached Ferris while he was receiving treatment from the physio and said: "I have done all I can. It has been noted. If I don't see it I can't do nothing about it. It has been spoken about and dealt with."