Sadiq Khan today sought to quash rumours that he plans to hand a job to Ken Livingstone, if he becomes mayor in May.
Current mayor Boris Johnson used his weekly Daily Telegraph column to claim that Khan had promised Livingstone a job, as the head of London's transport authority.
Johnson claimed he was "reliably informed" that Khan had promised the role of TfL chair to Livingstone, adding: "They are trying to put the band back together!" He called on Khan to be "volubly challenged" on the issue.
However, Khan today called Boris's claim a "porkie".
"I'd like to set the record straight," he wrote on his Facebook page.
"Ken Livingstone will not serve as Chair of TfL during my Mayoralty. It's too important a role to leave to someone else - I'll always do the job myself."
A spokesperson for Khan confirmed to Politics.co.uk that Livingstone would not be offered any job at TfL, or in any other part of the Greater London Authority family, while Khan was mayor.
Khan's statement is the latest attempt by Labour to distance themselves from Livingstone.
A senior source in Khan's campaign told Politics.co.uk last week, that Khan had no plans to be seen on the campaign trail with Ken, adding that "he is not part of our team".
Khan had originally sought an alliance with Livingstone, when seeking Labour's nomination. The two men were pictured together last May as Livingstone endorsed Khan for mayor.
There were rumours at the time among Khan's rivals for the Labour nomination, that Khan had offered a job to Livingstone in trade for his endorsement.
However there has been a notable distancing between the two men since Khan won the selection and Corbyn won the leadership.
While Khan has taken a deliberate strategy of distancing himself from the Labour leader, Livingstone has increasingly been seen as his biggest public cheerleader within the party.
Khan took a jab at Corbyn and Livingstone's record with Jewish Londoners last year, telling the Jewish Chronicle that Labour had to move away from its "unacceptable anti-Jewish" image, adding: "I want to reassure you I'm not like the last guy".
The former mayor has also had little to say about Khan in recent months. In a piece for the Evening Standard last week, Livingstone urged Londoners to "vote for Jeremy Corbyn’s vision of a better city," without once mentioning Khan by name.
Khan's distancing from Livingstone stands in stark contrast to Zac Goldsmith, who has repeatedly praised his predecessor. Boris has featured heavily in all Conservative campaign material during this election campaign.