Antisemitism in the Labour Party has been "fuelled" by social media posts done in the name of its leader Jeremy Corbyn, a major report has found.

Antisemitism watchdog the Community Security Trust (CST) said there was "no separation" between "generic pro-Labour Twitter accounts and campaigns" and "abusive Twitter accounts that claim to act in support of Labour in order to shut down allegations of antisemitism against the party."

CST's report, published on Sunday, said the "flow of antisemitic tweets" often use "hateful language to attack Jewish Labour MPs or other people who raise concerns about antisemitism".

It also noted many tweets "claim that any mention of antisemitism is part of a conspiracy to ‘smear’ Corbyn and Labour".

It identified 36 accounts that it dubbed "the engine room". It said each of the accounts have worked to build a narrative that Labour antisemitism is "exaggerated, weaponised, invented or blown out of proportion".

They often promoted content from leftwing websites that have attacked allegations of Labour antisemitism such as The Canary, Swawkbox and Electronic Intifada.

The CST report said a third of these accounts had themselves tweeted antisemitic content.

The accounts include prominent accounts such as @SocialistVoice, which has 67,000 followers, former Labour MP George Galloway and pro-Corbyn social media outrider @Rachael_Swindon.

@SocialistVoice has the most engagement of any Twitter account talking about "Corbyn". 

The account holder Scott Nelson was expelled by the pary for tweeting about companies having "Jewish blood" and posting an image of the BBC logo with the Star of David replacing the C.

"He claimed that he was the victim of antisemitism smears and that he wouldn’t be silenced in his support for Jeremy Corbyn, noting that his desire to re-join the party was entirely dependent on Corbyn still being present," CST wrote of the account.

@Rachael_Swindon has tweeted about "Rothschild" influence - for which she later apologised - and repeated the "£1million trope" - a false claim that Israeli operatives offer a cash bounty to people willing to undermine Mr Corbyn, which orignates in the controversial Al Jazeera documentary The Lobby.

The documentary claimed Israeli embassy officials offered Labour Friends of Israel £1 million for Labour MPs to visit the Jewish state.

She tweeted "Don't get much for a million quid these days" in response to the news LFI did not have a stall at the party's annual conference.

The accounts' response to last month's BBC Panorama about Labour antisemitism was "striking in its consistency and its coordination".

"They retweeted each other and developed related hashtags, even discussing the use of Twitterstorms to try to dominate the online conversation about the programme," CST's report said.

"It was a case study demonstrating exactly the same online behaviour identified in this research and described in this report."