Jeremy Corbyn was a member of a private Facebook group in which members published dozens of anti-Semitic messages and holocaust denial theories, it emerged yesterday.

Labour last night confirmed it was investigating up to half a dozen party members for their involvement in the group, with Corbyn allies Clive Lewis and Chris Williamson identified as members of the group.

Messages published on Palestine Live include conspiracy theories about the Rothschild family, supposed Israeli involvement in the 9/11 attacks and links to material produced by neo-Nazi groups.

In one of the more disturbing posts, an image was posted of a pig with the words “Israel Lobby” branded on its side, which showed four politicians suckling from it.

Last night a spokesman for Mr Corbyn confirmed that the Labour leader had previously been a member of the group but did not have any knowledge of anti-Semitic posts published in it.

Both Mr Williamson and Mr Lewis said they were unaware of any anti-Semitic or racist content on the group and had now removed themselves from it.