The world governing body told BBC Sport Wales:
“World Rugby has clarified to the Wales team management as part of the usual review process with teams that the TMO made an error in the application of law during the England versus Wales match at Twickenham. In accordance with law 21.1 b Wales should have been awarded a try as the Wales player grounded the ball.”
A frustrated Warren Gatland described it after the match as a “terrible mistake”
Wales head coach Warren Gatland criticises TMO decision
Gatland’s assistant Rob Howley also claimed Alain Rolland, the former referee who heads up World Rugby’s team of elite match officials, has spoken to the Wales camp to admit to the error on behalf of his personnel.
“I know Warren Gatland spoke to Alain Rolland, and they confirmed that the TMO made a mistake,” said Howley.
“It was good to have dialogue with World Rugby. That phone call took place – I think it was Monday – and Alain Rolland confirmed on behalf of World Rugby that the TMO made a mistake.
“It’s happened. It is disappointing that happens in professional sport, but we focus on the next two weeks and getting ourselves ready for Ireland.
“There was plenty of time after that decision. We had a couple of opportunities which we should have taken.”
Wales lost 12-6 at Twickenham, to end their hopes of a Grand Slam. They will be looking to get their Six Nations campaign back on track in Dublin.
However winger Alex Cuthbert is out, because of a knee injury.
Watch every match of the June and November Internationals streaming live on RugbyPass, home of the world's best global rugby coverage including news, highlights, previews & reviews, fantasy, live stats, and more!