Labour are hailing the defection of Councillor Shahed Ali, deputy leader of Respect on Tower Hamlets council.
Cllr Ali said his decision to resign from Respect "was taken after months of listening to local community organisations and residents of Whitechapel ward over the last few months."
Ali called on councillors in Tower Hamlets to "combine our efforts to halt the progression of the far-right" adding "I believe the best way to do that is by being part of today’s Labour Party."
