Bookies Paddy Power and Ladbrokes have revealed their odds for this year's contenders for the UK Christmas No.1 chart spot.Both firms told MCV they make Call of Duty: Black Ops 2 the favourite, ahead of FIFA 13 and the likes of New Super Mario Bros U, Medal of Honor: Warfighter, Assassin's Creed 3 and Halo 4.Alex Donohue of Ladbrokes said: "It would be one of the upsets of the year if Black Ops didn't land the top spot this Christmas."The Elder Scrolls V: Skyrim claimed the Christmas No.1 spot last year, marking the first time in eight years the Xmas top spot didn't go to an EA or Activision game.