England have revealed that Joe Marler has apologised to Samson Lee for verbally abusing the Wales prop in Saturday's 25-21 RBS 6 Nations victory at Twickenham.
Tournament organisers have confirmed they are investigating an incident in the first-half in which Lee appears to be heard on referee Craig Joubert's microphone being called a "gypsy boy".
Angered by the insult, Lee squared off with Marler and a statement released by the Rugby Football Union on Sunday afternoon confirmed the Harlequins loosehead was responsible for the remark.
"Joe spoke to Samson at half-time to apologise and he was reminded by [head coach] Eddie Jones of his responsibilities as an England player after the game," the RFU statement read.
Verbal abuse of a player based on religion, race, colour, national or ethnic origin, sexual orientation or otherwise carries a minimum sanction of a four-week suspension.
Marler's apology has led to speculation that his Six Nations participation is effectively over for this campaign as England seek to complete the Grand Slam in their final match of the Championship against France in Paris on Saturday.
Wales, who saw their own title hopes fade with their defeat at Twickenham, welcomed Marler's apology. "We're disappointed by the comment made and pleased Marler apologised to Samson and was reminded of his responsibilities as an international rugby player," a Welsh Rugby Union spokesman said.
Adding to Marler's woes in an eventful first half for the Harlequins front row was an incident in which he appeared to land a forearm in the face of Wales prop Rob Evans, an offence which carries an entry-point sanction of two weeks.
"We are aware of the incidents and are establishing the facts at this moment," a Six Nations spokesperson told Press Association Sport.
A Six Nations spokesperson also announced the citing of Wales prop Tomas Francis as part of the tournament's disciplinary update for the weekend.
The citing officer has up to 48 hours after the final whistle to make a complaint.