England captain Owen Farrell has been suspended for four matches - meaning he will miss the first two games of the Rugby World Cup.
He had been given a red card for a tackle deemed dangerous during a Wales game earlier this month - but this was downgraded to yellow.
Farrell's shoulder had struck the head of loose-forward Taine Basham during England's 19-17 warm-up win on 12 August.
World Rugby subsequently appealed against the downgrade, and an independent disciplinary hearing has now upheld the red card.
Basham failed a head injury assessment after the controversial tackle - and the decision that it was only a sin-binning offence led to a furious outcry from pundits and player welfare advocates.
The captain could have faced a six-match ban, but it was reduced to four because of his "acceptance of foul play, clear demonstration of remorse and his good character".
Farrell had voluntarily stepped down from England's game against Ireland last Saturday, meaning this match counts towards the punishment.
He will also miss an upcoming warm-up against Fiji at Twickenham Stadium this weekend.
But in a bigger headache for England, Farrell will be unavailable for crucial Pool D matches against Argentina and Japan when the World Cup begins in France on 8 September.
He will only be available for the final pool games against Chile and Samoa.
Farrell isn't the only England player who is likely to miss early games in the tournament.
Eighthman Billy Vunipola is facing a similar suspension after being dealt a red card during the Ireland game - and a verdict in his hearing is expected on Wednesday.
Veteran scrumhalf Danny Care has told reporters that preparations are well under way for the World Cup.
England have a good record at the tournament having won it in 2003, and been runners-up three times, including in 2019.
"It has been a lot for Owen to deal with," Care added. "The way he has handled everything that has been thrown at him has been exceptional.
"Some of the stuff you have seen written about him has been horrible. He has kept his head down and taken to it with the utmost dignity.
"He is the same old Owen, still driving standards on and off the pitch. You wouldn't know he has had all this stuff going on behind the scenes and it shows you the nature of the man, how much he cares about this England team."