The Labour Party in Tower Hamlets says it has upheld a decision to expel five councillors after they supported opposition candidates in a by-election.
Kabir Ahmed, Rofique Ahmed, Shahed Ali, Abdul Asad and Shafiqul Haque had appealed against their expulsion.
The Labour Party said they campaigned for independent candidate Gulam Robbani in the by-election in Spitalfields, east London, in April.
Mr Asad said the councillors were taking legal advice.
Leader of the Labour group, Councillor Joshua Peck, said: "You cannot campaign against the party and expect to remain a member."
All five men remain Independent councillors for Tower Hamlets.
Labour was narrowly defeated in the by-election by Mr Robbani.