The Times newspaper used the Freedom of Information Act to ask police forces how many crimes went uninvestigated. From the replies they got from 21 out of 43 forces the answer was about 650,000 out of around two million crimes in 2010. So one in three known, reported crimes are just ignored.
What I would like to know is how many are uninvestigated when the suspected victim is a freemason. And how many are uninvestigated when the suspected culprit is a freemason. That would be fascinating, but something we will never know, because freemasonry is a secret society.