Scotland Yard investigations into gay murders in the 1990s were marred by "institutional homophobia", a police watchdog has said.
Improvements have been made since the Colin Ireland murders
But standards have "improved dramatically" in recent years, said the force's independent Lesbian Gay Bisexual Transgender (LGBT) group.
The advisory group has just completed a review of 10 gay and transsexual murders between 1990 and 2002.
Five members involved in the report have been awarded police commendations.
Bob Hodgson of the Advisory Group said: "There were serious shortcomings with the investigations in the 80s and 90s."
But more recently, he said the force had demonstrated an "effective and professional approach" to solving murders in the gay community.
He cited the probe into the 2005 murder of barman Jody Dobrowski as an example of fine police work.
The report calls for a more effective system for warning people when particular areas become dangerous for the gay community.
Among the cases examined in the review were five murders in 1993 by Colin Ireland, who attacked gay men he met in pubs.
The report found the investigation was "hampered by a lack of knowledge of the gay scene in London".
Commander Dave Johnston said the Met had "learned from past investigations" into homophobic crimes.
"This has resulted in increased confidence in the service we deliver to the LGBT communities of London," he said.