There will be no grand slam in this year's Six Nations. There is no unbeaten team after three rounds, the first time that has happened since 2006 when France won the title on points difference from Ireland.

The tournament has twisted and turned. France defeated England, Ireland thrashed Wales who then humbled France and England pipped Ireland in the match of the year so far. The common theme was that the home side prevailed on each occasion and there have so far been two away victories, England at Murrayfield and Scotland in Rome.

If home advantage continues to hold sway in matches involving the top four sides, England will probably emerge as champions. They face Wales at Twickenham in the next round before finishing in Italy, for whom a whitewashed wooden spoon beckons after the heartache of defeat to Scotland in the final minute.

France's final match is at home to Ireland, but before then they have to visit Murrayfield. They will be without the centre Wesley Fofana, who has been a constant in a time of flux, and they have dropped the No8 Louis Picamoles for making a disrespectful gesture to the referee Alain Rolland after being shown a yellow card in Cardiff.

France should not be discomfited by the state of the Murrayfield pitch given the poor state of the surface at Stade de France, and the turf at the Millennium Stadium was one of the reasons why the scrum last Friday degenerated into the shambles that disfigured matches until this season's change in the engagement sequence. Rolland sent two players to the sin-bin, as he did when Wales played South Africa last November, but it was not all jiggery pokery.

France's collapse was as bad as any of the scrums. They had anticipated that Wales would start furiously after a chastening defeat in Dublin, but they were 11 points down in 10 minutes and showed little of the collective will and strength that England had after falling behind by a bigger margin in Paris earlier in the month.

They have regressed since the last World Cup. If they were dysfunctional in New Zealand, they had the resolve to overcome selection whims and comic outbursts from their then head coach Marc Lièvremont to reach the final where they lost to New Zealand by a point, but under Philippe Saint-André they have become shapeless and their attempts to play so far behind the gainline against Wales was exactly what the home side wanted.

Saint-André has benefited, if that is the word, from a new agreement between the Top 14 sides and the French Rugby Federation over the release of players, but such is the power of the clubs, cash rich and able to attract leading players from all over the world, that it is far removed from the two-way alliance that has worked so effectively in England.

Club owners are already cursing the agreement and ignoring some of its provisions. Such are the salaries that they are paying players, the Top 14 is becoming like football's Premier League in England, the driving force of the game. Saint-André is fighting the system, but he is not making the most of what he has and sympathy evaporates when France have such a poverty of ideas that blighted their display against Wales.

They remain one of four sides in contention for the title, along with England, Ireland and Wales, but they look far from champion. Wales stirred themselves after being outmuscled in Dublin, but England will be brimming with motivation at Twickenham after last year's 30-3 defeat in Cardiff when they not only missed out on the grand slam but lost the title to their hosts.

Ireland were primed against Wales, the reheating of Brian O'Driscoll's omission by Warren Gatland from the final Lions Test in Australia masking Ireland's prime focus which was a reaction to Wales's stated ambition of becoming the first team to win the Six Nations in three consecutive years.

Their head coach, Joe Schmidt, adopted a typically New Zealand approach, turning Wales's strengths, in particular the breakdown, into weaknesses. By keeping risk to a minimum, they denied their opponents mistakes to feed off, but against England they played a wider game and were unable to force the penalties they had earned in the previous round.

Penalties were Wales's staple against England last year as they dominated the scrum. They will be heartened by the appointment of the French referee Romain Poite to take charge at Twickenham: he has a reputation for rewarding the dominant scrum and it was the one area England struggled in against Ireland, where Dan Cole was conspicuous by his absence.

If England deny Leigh Halfpenny the opportunities to kick for goal, as they did to Jonathan Sexton who lined up only one penalty, they will be on the road to victory, but in two matches against Wales under Stuart Lancaster they have not only failed to win but have not scored a try.

England's victory over Ireland was a fascinating tactical battle. The Irish often resorted to the unexpected and the home side were also wide boys, but Wales under Gatland have tended to play it one way, straight and direct. The task for opponents is not to anticipate what is coming but to deal with it, which Lancaster's men failed to do last year, although before their collapse they did blow two try-scoring opportunities.

The winner will go into the final round in contention for the title and both would expect to win their final match. Wales are at home to Scotland, opponents they have not lost to since 2007, while England are in Rome, the one team Italy have not defeated in the championship, although they have come close.

The kick-offs on the final day are staggered, giving France and Ireland, who will play the final match, the advantage, if they win next week, of knowing what they have to do in terms of points difference. The Olympic Stadium will long have been deserted when the final whistle goes in Paris.

This is an extract taken from the Breakdown, the Guardian's weekly rugby union email. Sign up here