Former rugby league star Jason Ryles has warned that England's joint training session with Wales to improve their scrummaging could create a lot of intensity between the players.
The nations' packs will warm-up for their opening autumn internationals by drilling their set-pieces in Bristol under the gaze of referee Nigel Owens after Steve Borthwick brokered an arrangement between the camps.
Eddie Jones will order his forwards to "rip into" Wales and experience has taught Ryles, an assistant coach at rugby league club Melbourne Storm who has been honing England's tackle technique on a consultancy basis, that hostilities can erupt.
"A couple of years ago the Storm trained against the Canterbury Bulldogs and it didn't work," Ryles said.
"It was a good concept which started out at two handed, then it went to bumping shoulders and then it was, like, **** it! So it didn't really work.
"It was a little bit different to this. England and Wales are both looking to improve their scrummaging but with the Bulldogs it was just that little bit too competitive - to say the least."
England captain Dylan Hartley though had a different view as he sees the move from Jones will benefit the players to come out of their comfort zone.
"I don't think we can go down there and have a brawl. That would be detrimental and we wouldn't get anything out of it. It's being refereed so it's definitely going to be beneficial for us," Hartley said.
"Going up against Wales might challenge us differently and make us a bit more resilient and self-reliant.
"It'll also bring a little bit more edge to the session, kind of heads on. The heads are pretty good when we're training with England but I can imagine preparing for that session will be different."
Jones believes the session against Wales will give England a perfect opportunity to improve their set-piece ahead of the autumn international clashes against Argentina, Australia and Samoa.
"It's a training session but we want them to be 100 per cent. Absolutely 100 per cent," Jones said.
"We want to be the best scrum in the world and we just feel that when we scrum against each other there's a certain amount of familiarity.
"We need our scrummaging to go to another level so we want to be challenged in that area. It's something different."