Five Nottingham city councillors have quit Labour to form a new party.
Councillors Kirsty L Jones, Imran Jalil, Anwar Khan, Naim Saqab Salim and Faith Gakanje-Ajala have formed the Nottingham People’s Alliance.
The new party will be the Labour group’s official opposition on the authority.
A sixth councillor, AJ Matsiko, is also joining the new party after resigning from the Labour group in April.
The Labour group still has a majority on Nottingham City Council, with 43 councillors, and has run the authority since 1991.
But the move means the Nottingham Independents, made up of three councillors, no longer form the opposition.
Jones, who represents Mapperley, is the Nottingham People’s Alliance’s interim leader.
She pointed to the city council’s recent cuts and a loss of trust with the national party.
Jones said: “Labour has failed my community, our city and the country. I think it is dead to be honest.
“This is the beginning of the end of the Labour party’s dominance over Nottingham.
“We are against council cuts, we want to improve the economy locally and we want to have the freedom to speak out about national and international issues which we care about.”
The other councillors represent Bilborough, Lenton and Wollaton East, Hyson Green and Arboretum and St Ann’s.
The Nottingham People’s Alliance added it disagreed with the way Neghat Khan was chosen as council leader last year, after the party’s National Executive Committee (NEC) stepped in to oversee the process.
The new party is linked to the Broxtowe Alliance, which runs Broxtowe Borough Council.
It was formed earlier this year when 20 councillors quit Labour to join the party in January to protest at the party’s direction under Sir Keir Starmer.
Nottingham City Council has been contacted for comment.