2009 in British music charts

This is a summary of the year 2009 in British music. 31 singles have occupied the number-one spot including 15 new entries. Due to the increase in downloads over physical sales, singles now tend to enter the chart at a lower position, before climbing to the top a few weeks later: a trend which was previously rarely seen in the later half of the 1990s and most of the 2000s.
Summary of UK chart activity
January
Alexandra Burke's "Hallelujah", the Christmas number-one single of 2008, remained at the top of the Singles Chart for a third week on 4 January. One week later, however, American singer-songwriter Lady Gaga's debut single "Just Dance" went to number one, and stayed there for the remainder of the month. Elsewhere in January, Girls Aloud scored their twentieth consecutive top ten single with "The Loving Kind", while Beyoncé returned to the top ten with "Single Ladies (Put a Ring on It)", the second single from her I Am… Sasha Fierce...