The Independent Police Complaints Comission (IPCC) has published a report highlighting failings in the working practices of the Southwark Sapphire Unit - a police department dedicated to investigating serious sexual violence.
It found that officers there wrote off allegations as "no crimes", so they could reduce the number of unsolved cases on their books and meet official crime detection targets.
Ronke Phillips reports.
More top news
Tributes have been left in Caledonian Road in Islington where 15-year-old Alan Cartwright died after he was stabbed.
A boy has died after he and his friends were attacked while cycling in north London.
Three police officers have been praised for their actions in helping a four-year-old boy who had become stuck on a roof in Newham.