Rio Ferdinand  has confirmed he will leave Manchester United  after 12 years at the club.Ferdinand, 35, became the most expensive British footballer in history when he moved to Old Trafford from Leeds United in a £29.1 million deal in the summer of 2002.He went on to make 454 appearances for the club, scoring eight goals and winning six Premier League titles, two League Cups and the Champions League in 2008."I have thought long and hard over the last few months about my future, and after 12 fantastic years playing, for what I regard, as the best club in the world, I have decided the time is right for me to move on," Ferdinand told his website, 5mag."I joined Manchester United in the hope of winning trophies, and never in my wildest dreams could I have imagined how successful we would be during my time here. There have been so many highlights, playing alongside some great players who have become good friends, winning my first Premier League title and also that fantastic night in Moscow are memories that I will cherish forever."Circumstances didn't allow for me to say goodbye the way I would have liked but I'd like to take this opportunity to thank my team-mates, staff, the club & the fans for an unbelievable 12 yrs that I’ll never forget. Winning trophies I dreamed about as a kid came true at this great club."I am feeling fit and healthy, ready for a new challenge and looking forward to whatever the future holds for me."