In the 2001 census Southampton and <answer>Portsmouth</answer> were recorded as being parts of separate urban areas, however by the time of the 2011 census they had merged to become the sixth largest built-up area in England with a population of 855,569. This built-up area is part of the metropolitan area known as South Hampshire, which is also known as Solent City, particularly in the media when discussing local governance organisational changes. With a population of over 1.5 million this makes the region one of the United Kingdom's most populous metropolitan areas.
What other city merged with Southampton after the 2001 census?
Portsmouth