The prospect of a second Welsh Grand Slam in four years is difficult to fathom after they limped out of the World Cup at the hands of Fiji, but home win against France on Saturday will secure it after victory in Croke Park at the weekend.

Wales flanker Jonathan Thomas, who was part of the team that beat Ireland in 2005 to lift the championship, always dreamt of a Grand Slam but never believed he would get the chance to experience two clean sweeps.

An estimated 250,000 descended on Cardiff for Wales' 2005 Grand Slam game decider and three years later 25-year-old Thomas is looking forward to a similar party atmosphere in the Welsh capital in this Saturday's title decider with France.

The French need to win by 20 clear points to wrestle the title from Wales' grasp — something Thomas and his unbeaten Wales colleagues are determined will not happen.

"Playing for Wales at the Millennium Stadium for the Grand Slam is what you dream of," said Thomas, one of 10 survivors from the 2005 squad. "I can still remember vividly that day in 2005. My overriding memory was the bus journey into Cardiff.

"Playing for Wales is one of the most special things you will ever experience and you always look forward to seeing the supporters when you are go into the stadium.

"But that day it blew all the players' minds as we struggled to take in actually how many people were there supporting you. There were literally thousands of fans and it was just a sea of red through the Cardiff streets."

Since Wales' World Cup exit last October new coach Warren Gatland has transformed the nation's fortunes and only 80 minutes now separate them from a championship clean sweep following victories over England, Scotland, Italy and Ireland.

"When you grow up you dream of being a part of occasions like that and it is wonderful to be involved twice in four seasons.

"It makes it all the more special because we have been through bad times together over the last 12 or 18 months," said Thomas.

"We have worked really hard and not to achieve what we wanted during the World Cup was so disappointing. So to be going for the Grand Slam so soon after is a testament to the players and the coaches how things have been turned around."