Former international stand-off Andy Goode still believes that the biggest threat to England's dominance will come from Ireland.
Joe Schmidt's men struggled to overcome a much-changed France on the opening weekend and escaped with a victory thanks to Johnny Sexton's dramatic last-minute drop-goal, but impressed against Italy.
Meanwhile, Eddie Jones' side were comfortable winners in round one, defeating the Azzurri 46-15 at the Stadio Olimpico after scoring seven tries in Rome.
They followed that up with a tense 12-6 triumph over Wales, who have performed well so far in the competition.
The Red Dragons could therefore come into the equation alongside Scotland, who put their loss to Warren Gatland's team behind them by emerging 32-26 triumphant over France, but Goode insists that the Emerald Isle will be England's toughest opponent.
He said: "It's going to be really tight. Ireland are a massive threat to England's dominance, no team's won it three years on the trot and that could be England this year.
"Ireland are exceptionally well coached by Joe Schmidt, they've got some quality throughout the squad, Wales are in a rebuilding process but, if they can continue to play like the Scarlets in Europe, then they're a threat."
The Red Rose also have to contend with injuries, after seeing a number of players from the squad go down, but Goode does not believe that they are hampered too much.
"All the news about injuries in England but ultimately it's only Billy Vunipola and Elliot Daly who are out injured from our starting team," he added. "It's still a pretty strong England team isn't it?"
England are 10/3 to win the Six Nations again this year with Wales 250/1.
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