England open their campaign in the cauldron-like atmosphere of the Millennium Stadium when they face resurgent Wales on February 5.

That is quickly followed by the visit of France the following week and a trip to Ireland two weeks later.

If England can go through those games unbeaten they will be well on their way to the title but former England captain Johnson - who announced his retirement from competitive rugby on Monday - believes it is a monumental task.

"They have got a very difficult start, there is no doubt about that," Johnson said. "I can't remember ever playing a Six Nations when we had that sort of start."

Despite England's daunting opening, the World Cup-winning captain is convinced coach Andy Robinson's men will rise to the challenge of playing in such high-intensity fixtures.

"England have to play away at Wales, who will obviously be keen to win, and then it is France at home which is a huge game," the 34-year-old said.

"Ireland away will be another huge game so it is going to be a tough start and a huge challenge, but I am sure they would not want it any other way. I am excited about watching those opening games."

England's preparations have been hampered by a catalogue of injuries to key players, most notably to captain Jonny Wilkinson, and they appear to be struggling badly for midfield resources.

But Johnson believes there is enough strength in the English Premiership to cover the loss of players like Wilkinson, Mike Tindall, Will Greenwood and Stuart Abbott.

"There are a lot of injuries around which is going to make things difficult for England," Johnson said.

"But, as ever, injuries give a chance for someone else to come in and play, particularly in the centres.

"There are lots of guys who have gone down but there are a few who can come in."

Johnson believes his Leicester team-mate Ollie Smith and Newcastle Falcons centre Jamie Noon could make up an exciting pairing in England's midfield.

"Jamie Noon and Ollie Smith have been some of the best centres in the Premiership," Johnson said.

"And if they get in and play fantastically well then people will be saying they should have been in a year or even two years ago.

"Injuries always provide an opportunity for someone else, and an opportunity for the team to blood players when other people are not about."

England coach Robinson has been critical in recent weeks of the number of games his players are expected to play and Johnson admitted he shared some of his views.

"There are a lot of guys going down injured at the moment and I think something does need to be done about the length of the season," Johnson said.

While Johnson does not want the intensity of the Premiership to be compromised, he is adamant that if future players are to enjoy careers as long as his, then the number of games needs to be reduced.

Johnson said: "The intensity of the games is a great thing because if you want to beat the best in the world you can't afford to have a soft domestic season.

"But we do need to be careful about how many games these guys are playing over such a long period. If players are playing for 11 months a year then there is no chance to recuperate and train properly and regenerate themselves."