Sir Keir, the former head of the Crown Prosecution Service, said: “Sadiq and I go back a long way – we first met when he was a lawyer, standing up for the victims of racism, of prejudice and of discrimination.
“I’ve always been inspired by his journey – from growing upon a council estate to becoming Mayor of our great capital city.”
Mr Khan, 50, often refers to being the son of a bus driver. At the launch of his re-election campaign earlier this month, Labour’s deputy leader Angela Rayner dubbed him “council estate Sadiq” and said he was “bossing” the best capital city in the world.
Sir Keir, the Holborn and St Pancras MP, said the mayoral elections were “crucial” to determining London’s future after the pandemic. He said Mr Khan showed what Labour could achieve in power.
He said: “Over the last five years, Sadiq has shown the difference Labour can make in power. Building record numbers of council homes, investing millions to support young people who’ve been hit hardest by the lockdown and reducing toxic air pollution by more than a third.”