LONDON (Reuters) - Kung Fu Panda 2 shot to the top of the UK box office charts over the weekend with one of the biggest opening takes of the year, according to Screen International on Tuesday. Voiced by Jack Black, Po the Dragon Warrior panda took 6.18 million pounds to knock the X-Men off top spot. Boozy comedy The Hangover Part II, stayed in second place with X-Men: First Class, down at three. Johnny Depp blockbuster Pirates of the Caribbean: On Stranger Tides slipped a place to fourth, just above teen dance movie Honey 2 which came in at five. Diary of a Wimpy Kid 2 was down two at six while Formula One biopic Senna slipped one spot to seven.