England hooker Dylan Hartley has been dropped from England's World Cup squad after his latest suspension.
The Northampton Saints skipper was cited after a headbutt on Jamie George in last week's Premiership semi-final and was this week handed a four-week ban.
As a result he would have missed all of England's World Cup warm-up games, as well as their opening pool fixture against Fiji.
Hartley has decided not to appeal the sanction handed down to him and will be replaced by Jamie George in the World Cup squad and will not be considered until the suspension is served.
"We are obviously very disappointed with the situation that Dylan has put himself in and where that leaves us as a squad," said England Head Coach Stuart Lancaster.
"I have spoken to him and he knows he has let himself and everyone down.
“If we selected him in the World Cup squad he would have played no competitive rugby at all and we would be left exposed with only two available hookers in what is a specialised position going into the Fiji game. All it would take is one injury (that is not tournament ending) during the week of the Fiji game and we would only have one fit hooker in the squad for our crucial opening game and this would leave us massively exposed.
"In addition, the regulations also clearly state that in our World Cup Squad we must have sufficient cover that is suitably trained and experienced in the front row in case of injury. This is clearly not the case if we begin the tournament with a suspended hooker and as such we have been left with no choice but to replace him.
"It also goes without saying that we need all our players to be able to control their discipline and make good decisions under pressure, the World Cup will clearly require this, and Dylan has not clearly displayed this in this latest incident. This is an area that he still needs to address.
"Jamie has obviously played well for Saracens this season and I’m sure will work extremely hard to take his opportunity.”
Hartley added: "I am devastated with what has happened and the position I have put myself and the England team in. I would like to apologise to Jamie, Stuart, and my team mates both at Saints as well as England. What happened is not acceptable and I understand why this decision has been made."