Ulster and Matt McCullough have "strenuously" denied allegations made by London Irish that the player racially abused right wing Delon Armitage after the two teams met in the Heineken Cup last weekend.
In a statement yesterday London Irish referred to "alleged racial abuse" which apparently took place after the game, and they forwarded their "version of events to ERC" after considering the matter with club officials and Armitage.
Ulster have today reacted angrily to the allegations, claiming that while McCullough admits foul and abusive language, he and the club deny racial abuse.
"An explanation has been made by Matt McCullough to Armitage and London Irish that whilst it is acknowledged that foul language was used in the heat of the moment during a highly charged match, there is a complete denial that anything was said that either was, or was intended to be, of a racially derogative nature," a statement from Ulster rugby said.
"Ulster Rugby and Matt McCullough would like to make it unequivocally clear that no admission or apology for the use of racist language has been made either expressly or impliedly to Armitage or London Irish.
"Ulster Rugby and Matt McCullough take the allegations made by London Irish extremely seriously and will vigorously defend their unblemished record in relation to racial issues.
"London Irish have now formally presented the matter to the ERC, the Heineken Cup's governing body, and Ulster Rugby will not comment further at this point," it concluded.
The Exiles yesterday acknowledged that McCullough had been in touch with Armitage but nonetheless decided to pursue the matter further.
This course of action shocked Ulster's chief executive Michael Reid who had discussed the issue with an official from London Irish, Kieran McCarthy, yesterday morning.
Reid claims that his understanding following that conversation was that a joint statement would be issued by the clubs, stating that McCullough had apologised for his outburst, but that it had no racial overtones.
"Matt did use foul language towards the player (Armitage) in the heat of the moment at the end of the match but denied using any racist words or comments," said Reid yesterday.
"I spoke to a number of senior (Ulster) players and am happy with the accuracy of detail provided by the player and that it was a fair account of what transpired. If I thought for one second the player, any player, had a case to answer I would come down on them like a ton of bricks. We wouldn't accept or tolerate that behaviour."