Jeremy Corbyn on Wednesday launched his independent general election campaign against Labour in north London.
Mr Corbyn was last week officially kicked out of the party he used to lead after announcing he would stand in Islington North - where he has been MP for more than 40 years.
In a speech to campaigners he is expected to say he would be “an independent voice for equality, democracy and peace”.
He is due to add that he will represent those “who aren’t being served by our political system…who aren’t being heard” and whose “demands fall on deaf ears.”
In response to Mr Corbyn announcing his candidacy, Labour rushed through its selection process and chose Praful Nargund for the seat on Friday.
Labour had whittled down its search for Islington North to two candidates — Sem Moema, a member of the London Assembly, and Mr Nargund, with the winner originally due to be announced on June 1 after an online hustings.
Mr Nargund, an Islington councillor, said: “I promise to be a truly local MP, that represents all families and businesses that call this special place their home.
“Only Labour can change the country and fix 14 years of Tory failure.”
Mr Corbyn’s campaign launch comes as Labour risked being plunged into civil war amid confusion over whether pioneering MP Diane Abbott would be allowed to stand for the party at the general election.
The Hackney North MP, a longtime ally and friend of Mr Corbyn, had her suspension for saying Jewish, Irish and Traveller people do not face racism "all their lives" lifted on Tuesday.
But Ms Abbott said that she had been barred from standing for Labour.
Sir Keir has denied the claims and said no decision had been taken on whether she could be a Labour candidate had been made.
