16:00The Official Chart on Radio 1 with Jack Saunderswith Olly Murs: Greg James sits in for ReggieBBC Radio 1 Duration: 3 hours Sun 25th Nov 2012, 16:00 on BBC Radio 1 EnglandGreg James sits in for Reggie Yates to count down the Top 10 and reveal the UK's new Official No 1 with all the videos streamed live online at bbc.co.uk/radio1.GenresMusicPop & ChartEntertainmentBrandThe Official Chart on Radio 1 with Jack Saunders Source: BBC Online