England might have won their first Grand Slam in 13 years but according to World Cup winner Martin Johnson they have proven absolutely nothing yet.
Eddie Jones's side head to Australia next month for a three-Test series against the Wallabies chasing a first win Down Under since 2010.
Johnson was the man in charge of England on that fantastic night in Sydney six years ago but the history books are not in England's favour - they have only won three times on Australian soil ever.
And while England are the Grand Slam champions after their win in Paris in March - Johnson knows that the acid test lies in the southern hemisphere.
Since taking over, Jones has made it clear his aim is to return England to the No.1 side in the world - a position they last held when Johnson was captain.
But this current England side cannot be classed alongside those World Cup winners of 2003 until they prove themselves on the other side of the world according to Johnson.
At the weekend England warmed up for their tour by scoring five tries to beat Wales at Twickenham 27-13.
'If you want to be the No 1 side in the world you have got to go and win Test matches Down Under,' said Johnson, who was speaking at this season's Premiership Rugby Final where he was meeting hundreds of youngsters from the national grassroots rugby initiative, the Land Rover Premiership Rugby Cup.
'I always think that if you want to be considered world-class you have got to win Test matches in the southern hemisphere.
'Beating those sides at home is one thing, and that can be quite tricky anyway, but it's another thing to go there and win.
'If you win a Test in the southern hemisphere you are doing well. There was a reason those were the four teams in the World Cup semi-finals. They were the best four.
'To go and win one down there will be very good for this team.
'It was great to get the Grand Slam and give the fans something to cheer about after the World Cup.
'There are some good players coming through and I think, hopefully they can carry and develop in Australia.'
Jones' 35 man squad for the tour included some left-field uncapped selections like Teimana Harrison, Ben Te'o and Ellis Genge.
And Johnson likes the blend put together by Jones and has backed them to claim at least one Test win against a Wallaby team that pumped England in the World Cup under Stuart Lancaster last year.
'Australia is a good tour for them right now,' he added.
'We would like to see them win at least one game - it would great to see it go down to a decider in the third Test.
'I think it will go to a decider, England to win the second one. Australia have got some injury problems and it is quite early in their season.
'Whichever team loses the first Test normally then wins the second one because they have got a bit of an incentive.
'It is a reasonable squad with some young guys, obviously we want to put our best team out and be competitive.
'But you have got to balance that with keeping people on the field, there will be injuries so there could be opportunities for young guys to come in and see a little bit of it.
'Even if they don't get to play - they will see what it's all about. The intensity of Test match rugby, the touring and what it takes to do that. It should be a great opportunity.'
A three-Test series against a side is a unique challenge in world rugby, and Johnson admits the team that thinks on its feet will be the one that emerges on top.
'When you play a team three times you get to measure yourself against them and make pretty big improvements week on week,' he added.
'As a team you have got to be able to adapt, whatever that is, tactics, intensity, whatever it takes.'