- Labour MP Alun Michael has held the seat since 1987
- In 2010, he won with a majority of 4,709
- It is Wales' biggest constituency according to the size of the electorate
- The turnout in 2010 was 60.2%
Stephen Doughty will be the new MP. He's increased Labour's majority slightly, but turnout was just 25%.
Counting begins to find out who voters in Wales' biggest constituency by population have chosen as their new MP.
It's the final day of campaigning before the Cardiff South and Penarth by-election.