The Six Nations has come to be defined by the excitement and tension generated at the end of matches rather than the quality of play.

England are still in contention for the title even though their outside backs have had little more to do than Pontypool’s when the Welsh club’s nine-man tactics proved successful in the 1970s and 1980s.

That says a lot about the Six Nations, even if, in defence of the England interim head coach Stuart Lancaster, he has turned a rabble into a coherent whole. Wales and England have made the fewest mistakes this tournament and they are the two sides contesting the title.

Italy and Scotland have made the most and they have a scrap in Rome to avoid the wooden spoon. Ireland and France have been tactically constrained at times, although Les Bleus were suckered into abandoning their territorial gameplan early on against England when play effectively became deconstructed by both sides enjoying turnovers.

Wales will win a third grand slam in eight years if they defeat France, something they have only managed in the tournament in Cardiff three times since 1982, and they will be worthy champions in the sense that they have been better than the rest.

They have played to their strengths, aggressive at the breakdown, strong up front and possessing a three-quarter line out of Jurassic Park. Wales have skill as well as size, but mindful of the way they failed to build on the grand slam of 2008, they do not take chances.

In terms of stereotype, they are more English than Welsh, functional rather than flair-fuelled, running in straight lines rather than jinking, feinting and darting. It has helped them achieve consistency, building on a strong World Cup campaign.

Wales lost to France in Cardiff two years ago after conceding tries through interception passes in their own half and they were similarly profligate in Paris last year. By stripping their midfield of a footballing presence, James Hook has been on the bench all campaign and Gavin Henson has not been called on, they have become largely predictable, but their three-quarters are hard to stop when they have momentum.

Wales will probably need more on the three-Test tour to Australia in June, but these days they at least have a Plan B. They have become hard to beat, physically fit and mentally resourceful, qualities Wales have not been renowned for since the fading of the glory years of the 1970s.

France were the pre-tournament favourites, but Wales were strongly backed despite going into their first match against Ireland in Dublin with five forwards injured and doubts over two of their key backs in the World Cup, Rhys Priestland and Jamie Roberts.

They then lost their captain Sam Warburton at half-time but Wales are able to absorb blows that would have floored them not long ago. The form of some of their players in the Heineken Cup in the previous two months had been less than average, while Munster and Leinster were demolishing all before them.

Wales were the far better equipped of the two sides and if their performances have tapered in the last two rounds, surprised by England and frustrated by the refereeing interpretations against Italy last weekend when the attacking teams in all three matches were regularly collared at the breakdown. Without Shane Williams, Wales had no one to sidestep the whistle.

Victory over France would give Wales the grand slam, as was the case in 2008, 1978, 1976, 1971, 1952 and 1950. Les Bleus have looked like the team that stumbled to the World Cup final, disjointed and haphazard, rather than the side that pushed the All Blacks to the limit.

Philippe Saint-Andre has fiddled in selection almost as much as his predecessor, Marc Lievremont, and France have been at their most dangerous when trailing and, abandoning caution, chasing the game. They have asked for the Millennium Stadium roof to be open, despite the wet forecast, leaving Warren Gatland to lament what he suspects will be negative opponents.

Wales should win, emulating the achievement of the 1970s vintage with a third grand slam in eight years. Posterity has lent a romantic, rosy hue to Welsh rugby then, but for all the wizardry of Gerald Davies and Phil Bennett, they often wore down their opponents, exerting themselves in the final 20 minutes, the hallmark of the 2012 side.

Wales have only led once at the interval this year, 9-3 against Italy, and they have conceded more points than they have scored in the opening period. It is different after the interval: Wales have won all four second-halves, averaging 17 points compared to six in the first 40 minutes.

It was how they performed in the World Cup. They have staying power. Their rivals just have power.