Hundreds of rape cases are being delayed by months because of a backlog in digital processing.
The London Assembly Police and Crime Committee heard that the issue is a major challenge for the Metropolitan Police, with delays of six to nine months.
The backlog is in cases where full downloads of material from phones and other devices are needed, or deleted messages need retrieving.
Committee member Caroline Pidgeon said that in Lambeth and Southwark there are 180 live rape cases, and 140 of those are facing delays, most of which are waiting for information from the forensic labs.
Caroline Pidgeon told London Deputy Mayor Sophie Linden:
Sophie Linden said she has been in discussions to increase funding, and that there is "massive pressure" on forensic teams working for the Met, for reasons including the huge investigation into the Grenfell Tower fire tragedy.
Nearly 5,000 sexual offences and 3,200 rapes have been reported to the Met so far this year according to the London Assembly. Reported sexual offences have risen 80% since 2011, and rapes by 140%.