Mark Bennett, who was first elected in 2005, died in hospital in the early hours of Tuesday morning, Lambeth Council confirmed in a statement to the press.
Mr Bennett had been Mayor of Lambeth since March 2013, and took part in the LGBT protest in Vauxhall last November, after a homophobic attack had taken place .
The much-loved Councillor was also a member of the Labour Campaign for Lesbian and Gay Rights. Tributes poured in through Twitter for the Mayor last night, with UK MP Tessa Jowell tweeting her condolences.
“Devastating news about Mark Bennett,” Jowell wrote. “Impossible to imagine Lambeth without him. He taught us all so much about civic pride, quiet leadership and precision. So glad we were able to greet the Queen together when she visited Ebony Horse Club before Christmas. We must work hard to honour his memory and the standard he set us.”