Image copyright Getty Images Image caption Megyn Kelly is a presenter for NBC in the US

American TV journalist Megyn Kelly is being criticised on social media for questioning why blackface is racist.

The former lawyer asked, "What is racist?" in a discussion about inappropriate Halloween costumes during a Tuesday morning episode of NBC's "Megyn Kelly Today".

"Back when I was a kid, that was okay just as long as you were dressing as a character," she said, referring to white people painting their faces black for Halloween.

After strong criticism online, Kelly emailed colleagues to apologise, writing: "The history of blackface in our culture is abhorrent; the wounds too deep."

Blackface has a history of perpetuating offensive and racist stereotypes of African Americans dating back more than 200 years in the United States.

"It's a tradition rooted in racism which is very much about the fear of black people and the laughing at black people," Dr Kehinde Andrews, Associate Professor in Sociology at Birmingham City University told the BBC in June.

Many on Twitter took the opportunity to explain why blackface is widely considered offensive.

"Open up a history book. White people used to paint their faces black and act out ridiculous black characters during the Jim Crow era," wrote user Annabel Lee.

Many suggested that dressing up to imitate African Americans stopped being acceptable in the 1950s, and questioned whether it had been appropriate when Kelly was a child.

Others questioned why a group of white commentators would have a discussion on blackface at all without the perspectives of African-American commentators.

Skip Twitter post by @potatodonuts Why did they have white folks discuss things like blackface in the first place? What did they expect, Megyn Kelly to somehow have some profound opinion when she has neither the experience nor the range?? — spACE channel five (@potatodonuts) October 23, 2018 Report

"I just don't think it's white people's place to tell us whether we can be offended over blackface or not. Especially since blackface has never been used against them to dehumanise and oppress them systematically," wrote user Bella Goth.

However, others suggested that it should be common knowledge that the practice is inappropriate.

"I've seen comments that blast NBC for not having a black person on the panel, but honestly, minstrel shows and blackface were a popular form of extremely racist mass entertainment in America through the early 20th century. People who comment for a living should know that," wrote journalist Jamelle Bouie.

Skip Twitter post by @jbouie I’ve seen comments that blast NBC for not having a black person on the panel, but honestly, minstrel shows and blackface were a popular form of extremely racist mass entertainment in America up through the early 20th century. People who comment for a living should know that. — b-boy bouiebaisse (@jbouie) October 23, 2018 Report

Some called on NBC to cancel the Megyn Kelly show, writing "this is not only tone deaf, she's flat out racist. I was not raised to think blackface was OK and I'm 46, from small town Pennsylvania," wrote @Seanbaby.

Others recalled when Kelly made headlines in 2013 for stating it is "historical fact" that Jesus Christ, a man born in the Middle East, was white, adding that Father Christmas is too.

Skip Twitter post by @pattymo The only time Megyn Kelly would have a problem with blackface is if the person is also dressed as Santa Claus https://t.co/LfObbMDVfU — Patrick Monahan (@pattymo) October 23, 2018 Report

By Georgina Rannard, BBC UGC & Social news