Between 1996 and 2004, the population of the city increased by 4.9 per cent—the tenth biggest increase in England. In 2005 the Government Statistics stated that Southampton was the third most densely populated city in the country after London and Portsmouth respectively. Hampshire County Council expects the city's population to grow by around a further two per cent between 2006 and 2013, adding around another 4,200 to the total number of residents. The highest increases are expected among the elderly.
What's the only other city in England besides Portsmouth more densely populated than Southampton? (If the question is unanswerable, say "unanswerable")
London