The most recent Home Office statistics 2006/7 show that of the 9608 firearms offences 35% ( 3362) occurred in London and 10% (960) in Manchester.
The population of Greater London was 8.3m and Greater Manchester 2.2m.
London has just over 31,000 police and Manchester has just over 8000 police.
As you can see the figures are to all intents comparable with London having just over 4 times the number of crimes, population and police officers.
Do any force have enough officers? No but there is only so much money available.
What is most worrying is that all Chief Constables and the Commissioner are being told their budgets will be cut in the coming years and they are virtually all claiming this will result in a reduction in frontline police officers.