A policy adviser to a Labour shadow minister has branded Countdown’s Rachel Riley a "bully" who is spreading "smears" with her condemnations of antisemitism, after she spoke out about the party's crisis over the issue.

Ms Riley, who is Jewish, has become a vocal campaigner about antisemitism since she received a barrage of abuse for sharing a video by anti-racist campaigners that condemned Jew-hate in football.

She has used Twitter to raise concerns about antisemitism and this week, on a Channel 4 News podcast, she discussed the issue of antisemitism and the problem of it among Jeremy Corbyn’s supporters.

Karl Hansen, who advises Shadow Transport Secretary Andy McDonald, hit out over Ms Riley’s activism.

He tweeted: “Rachel is a celebrity with 604k followers who smears her political opponents as antisemites and boosts troll accounts that are notorious for targeted campaigns of harassment. She isn’t standing up to bullying she is a bully.”

His Twitter account is set so only his followers can read his tweets but The Red Roar blog shared it.

Meet Karl. Karl reckons Rachel Riley is guilty of smears and bullying for speaking out on antisemitism. Karl is a political adviser to Andy McDonald, Labour's Shadow Transport Secretary. pic.twitter.com/3vBa5LpY2m

— The Red Roar (@TheRedRoar) January 10, 2019

Mr McDonald's office has been contacted for comment.

Last year, Mr Hansen was criticised for describing Israel as an “apartheid state.”

He tweeted an article Ha'aretz about the demolition of a Bedouin village, saying: "How anyone could read this article and deny that Israel is an apartheid state is beyond me."

Jennifer Gerber, director of Labour Friends of Israel said his comparison was “part of the wider BDS (Boycott, Divestment and Sanctions) campaign to demonise and delegitimise the world’s only Jewish state.

"An adviser to a member of the Shadow Cabinet should know better than to repeat such pernicious nonsense."