Tower Hamlets council is threatening to take the Government to court if it refuses to ban a march by far-Right group the English Defence League.
Leaders are warning of violence if the event goes ahead on September 3 and will seek a judicial review if Home Secretary Theresa May does not ban it.
A council source said: "Something must be done to prevent this demonstration. If a judicial review is the only way then that is what we will do."
The EDL told members in an online message to take "our message into the heart of militant Islam within our own country". The message added: "We will go where we want, when we want."
Last week the Home Secretary banned an EDL march in Telford, Shropshire, saying she was acting to protect communities and property.
A Home Office spokesman said: "The Home Secretary can only ban a march in London following a formal application from the Commissioner of the Metropolitan police. No such application has been received. The Home Secretary will carefully consider any formal application, subject to the relevant legal tests."
Tower Hamlets Labour group leader Josh Peck said: "The EDL march should be banned. The police are more than capable of keeping them under control, but that won't stop the tension and anger that could exist long after they have left."
London Evening Standard
