You also have to consider the details of these statistics.
There are 8,000,000 people in London. 13% of them are black. That is 1,040,000 black people.
There were 116 murders last year. "Almost half" of them were black people. Let's just round it up to half.
So out of one million forty thousand black people, there were 58 murders? That means .005% (.00005) of black people in London commit murder if each of those murders were committed by a different person. So obviously murder is not a big problem in the British black community, or some trend that needs to be examined. That is simply not an alarming stat at all.
That doesn't mean we can't examine the variables that lead to this type of criminal behavior. But based on those numbers, it's very obviously not their race that is causing it.