An aide to Labour's Mayor of London candidate has quit after it emerged that he had published a series of offensive social media posts. Shueb Salar resigned as a parliamentary assistant to Sadiq Khan after apparently posting homophobic and sexist messages on Twitter before being hired by the Tooting MP in 2014.

The staffer had allegedly urged "hoes", "bitches" and "faggots" to vote for Khan at the May election and in a 2013 message he posted a link to YouTube video, declaring "I had a feeling the Woolwich killing was probably fake."

The post was apparently published just a day after off-duty Fusilier Lee Rigby was murdered by Michael Adebolajo and Michael Adebowal in London. Khan suspended Salar after the Mail on Sunday questioned the Labour hopeful about the messages. Now the former parliamentary assistant has resigned.

"Sadiq acted immediately to suspend Shueb Salar as soon as he was made aware of these serious issues over the weekend. Shueb Salar has now resigned from his role as a junior member of Sadiq's parliamentary staff," a spokesman for Sadiq Khan told IBTimes UK.

The move comes after Conservative cabinet minister Chris Grayling questioned Khan's judgement over the hiring of Salar. "These comments have absolutely no place in modern society," the House of Commons leader said.

"The Mayor of London makes a large number of decisions about who to hire and how to spend public funds: his record shows Sadiq Khan can't make those decisions in a way that stands up for Londoners."

Khan is tipped to win the City Hall race and succeed the outgoing Mayor of London Boris Johnson. The latest opinion from YouGov for LBC Radio, of more than 1,000 people between 4 and 6 January, put the Labour hopeful ten points ahead Zac Goldsmith (55% versus 45%) in the second round of voting.