text: The track's release date was brought forward by five weeks after a cover version by X Factor's Fleur East topped the iTunes chart last week.
  Ronson thanked "boy wonder" Bruno Mars, who features on the track, "without whom there would be no jam".
  Ed Sheeran, who scores a 10th week at the top of the album charts, fell to number two in the singles chart, while Band Aid 30 climbed to number three.
  The physical release of Do They Know It's Christmas? saw the charity track climb nine places, but it was kept off the top spot by Ronson and the ubiquitous Sheeran.
  East, who is the favourite to win this year's X Factor, performed the Ronson track during the show's semi-final on Saturday 6 December.
  Her mentor Cowell, who chose the track after Ronson and Mars pulled out of performing the song themselves on the talent show, called it "one of the top three performances" in X Factor history.
  East later apologised to Ronson, calling it "an amazing song". "I don't think anyone expected my performance to be as popular as it was," she added.
  Speaking to the Official Charts company, Ronson refrained from mentioning East, but thanked "everyone who bought, downloaded or DJ'd Uptown Funk this past week."
  "It's pretty much the coolest thing ever," he added.
  Featuring  Mars on lead vocals, Uptown Funk is the first single from British producer Ronson's fourth album, Uptown Special.
  Inspired by the feel-good funk of the 70s and 80s, it was already available in several countries around the world.
  Two Ronson tracks - Stop Me and Valerie, a collaboration with Amy Winehouse - reached number two in previous years.
target: Mark Ronson has clinched his first UK number one with Uptown Funk.