England’s 2003 World Cup winning coach Clive Woodward has fired a warning to Eddie Jones’s men ahead of this year’s tournament.
England head to Japan as one of the favourites for the World Cup, alongside New Zealand and South Africa.
The Red Rose are in a tough group though with France, Argentina, USA and Sunday’s opponents Tonga also in Pool C.
And as officials clamp down on high tackles, Woodward has warned England about their discipline in the World Cup.
“There’s many strengths, they’ve got this very powerful team,” Woodward said.
“This is what I call an x-factor team. But quite a few of the starting XV have got a track record of losing it in a game when under pressure.
“There’s been a lot of focus on the rules regarding neck-high tackles, and if you’re playing (pool rivals) France and Argentina, top teams, and get a guy sent off then the chance of winning that game is going to be very difficult.
“We saw recently (Scott) Barrett get sent off for New Zealand v Australia and they had a record score against them.
“You need every single player to play under pressure and play within the laws of the game.
“That’s the only chink I see (with England), they’ve got a real chance if they can play in the right way and keep 15 players on the pitch.”
England captain Owen Farrell is altering his tackling in an attempt to stay on the right side of the laws.
Farrell twice escaped punishment in 2018 despite appearing to make no-arms tackles.
“Owen is not overly focused on that area [tackling],” said England defence coach John Mitchell.
“But he has made some adjustments based on last autumn.
“John Carrington, our strength and conditioning coach, is also my support on defence and he’s very good at working on tackle technique.
“There can be mitigating circumstances, but if your hands are in front of your shoulder you’ve got a better chance of making a proper wrap tackle.
“If your shoulder is ahead of your hands, then the law doesn’t look after you very well.”