Operators have described Hackney Council's decision to approve strict new licensing conditions including limited opening hours for new licencees as "disastrous".
The new "core hours policy" suggests closing times of 11pm on weeknights and midnight at weekends, although the council has said the document should be seen as a "guide" rather than a "blanket policy".
The authority for the London borough, famous for its diverse and thriving nightlife, also voted to double the size of a Cumulative Impact Zone (CIP) in Shoreditch.
The proposals had proved controversial with 77.5% of respondents to a council consultation believing the measures would have a negative impact.
Operators have described the decision as "disastrous".
Tim Foster of the Yummy Pub Company tweeted: "Shame on you all Tweets by MayorofLondon MayorofLondon how to lose an incredible economy from one who already has his license to trade I want to inspire the new, diverse, unique future operators. Trust this tweet, you'll regret it!!"
Jonathan Downey, behind London's Street Feast markets, added: "This is a disgraceful decision and a shameful failure of elected officials to listen to the views of residents. It is disastrous for the life and vibrancy of Hackney nightlife. This is not over though and we will not be ignored."
Chef Neil Rankin tweeted: "24 hour city my arse."