"Whoever loses England v Wales, their next game becomes a must win. They'll have to beat Australia just to stay in the tournament.
"But in a way it won't do England any harm at all. It's often the teams that have to fight and battle who will be in the best position come the end of the World Cup. If they win the group then it doesn't really get any harder, at least until the final."
Australia's visit to Twickenham on October 3 is already looming large, with England forwards coach Graham Rowntree revealing on Tuesday that 'we're watching them constantly as a group, that country are going places'.
Johnson, captain of the England team that won the 2003 World Cup following a 20-17 victory over the Wallabies in the Sydney final, views them as the most dangerous team on the global stage.
"Australia can be utterly lethal when it comes to scoring tries out of situations where there's nothing on, more so any other team in the world," Johnson said.
"They execute with their hands very, very well and suddenly they're in. They score tries and that makes them lethal.
"People perceive they have weaknesses here and there, but they're usually able to cover them up. They almost won a World Cup in 2003 when they couldn't really scrummage.
"If England get ascendancy in the scrum and the referee penalises Australia, it makes a big difference to the game. If he doesn't penalise, then it nullifies the advantage at the scrum."
-AAP