Prime Minister Gordon Brown believes England will stage "a tournament to remember" when the RFU hosts the 2015 Rugby World Cup.
The IRB Council today backed the RFU's bid to stage the world's third largest sporting event.
He said: "I want to congratulate the RFU and everyone involved in the successful bid to bring the 2015 Rugby World Cup to England. This is a fantastic achievement.
"I'm sure the whole country will want to play their part in making this the most memorable of Rugby World Cups.
"It really is a great opportunity to inspire a generation of young people to play the game and together with Sport England's £30million support for grassroots rugby, the sport has some exciting years to look forward to.
"This is yet another tremendous event to add to the country's decade of sport and another chance to show our nation's passion for sport and what world class facilities we have to offer. I'm sure it will be a tournament to remember."