New figures show almost half of people who have HIV in England, live in the capital.
That same study shows that the number of gay and bisexual men being diagnosed with HIV reached an all-time high last year.
Nick Thatcher reports.
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Police have stepped up patrols after a woman in her 40s was "dragged to the ground" in a park in east London.
Families living near Heathrow say they are supporting a group of activists facing jail for chaining themselves to the airport's runway.
Police were called to break up a "large fight" which involved a baseball bat, a man dislocating his shoulder and three arrests.