Two men, one in their 20s, the other in their 30s, were approached from behind just after 10 o’clock last night.
Both have now left hospital.
Detectives want to hear from any witnesses.
Detective Inspector Gary Castle, from the policing team in Lambeth, said: “We are acutely aware of the shock this attack will cause members of the LGBT+ community and I want to reassure people that an urgent investigation is ongoing to locate the person responsible.
“We recently announced the reinstatement of LGBT+ community liaison officers for each of our 12 BCUs in London to support and advise on investigations where homophobia is a motive, and to ensure the community has a dedicated point of contact to address any concerns they may have.”
Anyone with information is asked to contact police on 101 or tweet @MetCC and quote CAD 7198/13Aug. You can also provide information anonymously to the independent charity Crimestoppers on 0800 555 111.