article_snippet: But figures released yesterday found that some have been missing for more than a decade.
article_snippet: But one force said today one force would not name police to protect police rights.
article_snippet: This equates to one officer being tasked with monitoring 51 sex criminals.
article_snippet: However most just receive one police visit a year after they have been released from prison. '
article_snippet: The figures emerged from Freedom of Information requests submitted to all police forces in Britain.
highlights_snippet: Greater Manchester Police lost 23 - but won't name Scotland Yard, UK's largest force over human rights .