London is generally a safe city. Like many other capital cities, it does have some violent areas and last year's riots didn't help, but it would not normally be considered a dangerous city by world standards, especially in the tourist areas.

To give you some idea, in 2009-10 there were 136 murders in the city as a whole. This is actually below the annual average, and in fact violent crime generally has decreased in the last few years. It very much depends on which part of London you are in as well - for instance, in Kingston upon Thames there have been just 12 murders in the last 10 years.

In this year's mayoral elections there were many arguments about the amount of crime in the capital, with each sides using different figures, but an overall drop in crime can definitely be detected - you can find some useful graphs and links here.