WINNING the Grand Slam has provided the single biggest one-day boost to the Welsh economy of all time, early figures from the weekend reveal.
Saturday was the biggest day Cardiff's economy has ever seen - bigger even than the opening day and the final match of the Rugby World Cup, both held in the city in autumn 1999.
Rugby fans keen to party spent a whopping £15m on food and booze during a weekend of celebrations.
About two million pints were downed in a day as the party stretched into the early hours with 200,000 fans inundating the city centre.
And over a million takeaways or sit-down meals were sold to starving supporters over the weekend.
Although shops were hit by a decline in traditional trading patterns on Saturday, the feelgood factor that gets people spending money in droves has already started to have a positive knock-on impact.
Across the country, shops have dressed windows with Welsh flags or messages of congratulations. Cars are still donned with flags and scarves and there is a spring in the step of shoppers and workers everywhere.
Paul Williams, Cardiff city centre manager, said, "It has been a fantastic weekend in the city, a weekend that I do not think has been equalled. A record-breaking weekend from every point of view - records were broken and shattered.
"Certainly it has not been like this for a generation, but on this occasion it started very early and went on all night and into Sunday. People were wearing the shirt, buying the flag, spending money eating and drinking.
"You are looking at figures of about £15m to the local economy on things like food and drink alone."
Mr Williams said shops in the city centre had seen a decline in normal Saturday takings of about 50% as people stopped shopping and were glued to the game.
"But as a city the impact was better than ever before. The shop owners know that people are ecstatic and that eases the pain," he said.
"The feelgood factor started on Sunday and shops have seen people spending positively since then. This win has changed the way we think and the city centre is now looking forward to building for the Rugby World Cup in 2007.
"But yes, this weekend has seen mega figures. Big numbers. You saw the crowd at the City Hall and every single spot of space was taken in the city centre."
Ian Everett, press officer of The Cardiff Initiative, said there will be a long-term boost for the tourism industry.
"The victory on Saturday will help push Cardiff even further into the limelight. Everyone here has known for years that Cardiff is a great city to visit, but now the rest of the world is catching on too.
"The match itself clearly provided a huge boost to the local economy. Every hotel and B&B in the area was full, and some bars even reported higher one-day takings than when Cardiff hosted the Rugby World Cup Final.
"There are long-term benefits too. Cardiff is already celebrating its centenary as a city and 50 years as capital of Wales this year, and the Grand Slam is a great anniversary gift that will ensure the city will be buzzing for months to come and is the place to be this year."
Even the Welsh farming industry is expecting to profit from the Grand Slam.
Gareth Vaughan, president of the Farmers' Union of Wales, has written to Wales coach Mike Ruddock congratulating his entire team for their outstanding achievement.
"I truly believe that this heralds the dawn of a new golden era for Welsh rugby - and I'm sure that a healthy diet of prime Welsh beef and lamb will help see the boys through to victory in the 2007 World Cup," he said.
Rodney Berman, leader of Cardiff Council, said the team had helped put the city on the map in an international context.
And councillor Nigel Howells, executive member for leisure, culture and sport, said, "Lifting the Six Nations Trophy is such a wonderful result for Welsh rugby that people will be talking about this victory for years to come.
"The build-up of expectation throughout the Six Nations has been amazing - and I'm sure the thousands of fans who came to Cardiff to watch the matches will agree.
"Cardiff is vibrant, alive and buzzing with excitement and as we celebrate 100 years as a city and 50 years as the capital of Wales, I'm sure everyone would like to send their congratulations to Mike Ruddock and all the team."
Pubs struggled to match the demand for beer, and Brains brewery said that it was a "record breaker".
Once again it had sold one week's worth of beer in one day. And over the course of the entire week profits were up a hefty 50%.
Outside the capital, souvenir stores were doing a roaring trade with a six-week waiting list for Groggs of the latest rugby heroes.
John Hughes, whose Grogg statuettes have been immortalising players for decades, said his Pontypridd-based business could hardly cope with demand.
Cardiff Airport also enjoyed a bumper weekend boosted by Irish visitors with 3,000 passengers going through its doors.
Bookmaking is the one industry to really suffer in Wales though, saying it faces a "catastrophic" week ahead, having to pay out more than £1.25m to patriotic fans who backed the Welsh side with odds of 50-1 at the start of the tournament.
Karl Williams, spokesman for Jack Brown, describes urging Western Mail readers to have a flutter at the start of the tournament as "the most catastrophic tip I have ever given".
"I did not realise how many readers would take this advice as hundreds of Western Mail readers are now at least £50 better off," he said.