Lewisham East Constituency Labour Party (CLP) chairman Ian McKenzie has caused outrage online after tweets emerged about shadow foreign secretary Emily Thornberry being gang-raped and beheaded by the Islamic State.

Mr McKenzie’s violent and misogynistic tweets, which said the Islamic State would not use Emily Thornberry as a sex slave but behead “and dump her in a mass grave,” were labelled as “vile” by Twitter users.

In a 2016 tweet Mr McKenzie appeared to contribute to a discussion about the shadow foreign secretary’s comments on the Islamic State.

The tweet read: “Emily Thornberry is too old for ISIS. They won’t make a sex slave of her. They’ll behead her and dump her in a mass grave.”

A 2015 tweet, which appeared to be on the same topic, said: “Maybe she’d agree sex slavery to one man only, provided he didn’t sell her on or insist gang rape.”

The tweets were brought to light by political activist and columnist Owen Jones to widespread outrage.

One user commented: “No-one should tweet what IM did – and there are clearly other tweets as well – without facing the consequences. He holds a position in the CLP. His views on women are just awful.”

Another said: “Do you think a member let alone Chair of a CLP should be tweeting stuff like that? Take a good long hard look at your values….”

“I would suggest you direct your indignation towards @iMcKenzied who actually wrote them…these tweets are vile,” another user added.

Mandu Reid, who is standing for the Women’s Equality Party in the Lewisham East by-election, said: “These tweets are abhorrent. They are clearly sexist and require an immediate apology. Then it will be up to Labour members to decide whether they think he remains a suitable person to chair the local party. If he is kept on it will signal, very clearly, just how invincible the Labour Party feels in Lewisham.”

Lewisham Labour declined to comment.

The Labour Party have been contacted for comment.