Haley Barbour: Romney to show America he is serious

The Republican Party has convened for its national convention in Tampa, Florida, where Mitt Romney was formally named as the party's choice to challenge President Barack Obama for the White House.

"This is the biggest opportunity with the biggest audience... He's going to make sure the American people know he's serious," former Mississippi Governor Haley Barbour said.

Speaking to the BBC's Katty Kay at the convention, Mr Barbour added he expected Mr Romney to appear "thoughtful, articulate, knowledgeable and committed" at the gala.