One reason for the flawed data is the way they are recorded.
In the US this incident would have resulted in the recording of at the very least 4 violent crimes.
In the UK it will only be recorded as one crime in their statistics.
http://www.bbc.co.uk/news/uk-england-london-15803860
Furthermore why do we not see these statistics?
http://www.ukcrimestats.com/Police_Forces/
Looks like 2012 was a busy year in violent crime in the UK to me.
Furthermore the US media has a lot to gain by bloating US crime statistics for the sake of the drama to push gun control legislation.
One thing is for sure that the crime rate for rape is higher in the UK than in any developed country. Explain this?