Labour was engulfed in a row over antisemitism this week after it emerged that one of its MPs, Naz Shah, had endorsed a plan to relocate Israel to North America.
Mr Livingstone took to the airwaves on Thursday to defend Ms Shah’s action but found himself also suspended after making a historical reference to Adolf Hitler in a discussion about Israel.
Mr Khan was the first high-profile Labour figure to call for Mr Livingstone to be suspended.
“Ken Livingstone’s comments are appalling and inexcusable. There must be no place for this in our Party,” the Labour candidate had tweeted around an hour after the controversial interview aired on BBC London.
However Mr Johnson, the outgoing Mayor of London, has tried to leverage the row over Mr Livingstone into the Conservative mayoral campaign.
He told LBC Radio on Thursday afternoon there was an “ideological continuum” between the two politicians, despite Mr Khan’s loud criticism of Mr Livingstone.
“There’s plainly some sort of virus of anti-Semitism within the Labour party that needs to be addressed,” he said.
“It seems to me there’s an ideological continuum between the views of Ken Livingstone about Israel and the position of Jeremy Corbyn and indeed the views of their candidate for London Mayor Sadiq Khan.”
The Tories’ campaign to elect Zac Goldsmith as Mayor of London has been forced to deny suggestions that it is running a “racist” operation.