There has been a surge of social media attacks on Rishi Sunak drawing on antisemitic conspiracy theories, casting the former banker as part of a “globalist” plot, with a sharp spike after Boris Johnson pulled out of the Conservative party leadership race. Tweets linking Sunak to the false notion of a globalist conspiracy – often a dog-whistle term of abuse used by the far right, antisemites and anti-vaccine extremists – were viewed more than 21.3m times amid soaring online abuse of Britain’s first prime minister of colour. The term was used by some last month to suggest that Grant Shapps, who is Jewish, and Sunak, a British Asian who worked for banks including Goldman Sachs, are somehow disloyal to Britain or are in the pockets of a global financial elite. Jewish groups and campaigners condemned commentators and media outlets including Nigel Farage and GB News for calling Shapps a globalist. Sunak was mentioned in 16,935 tweets containing the term “globalist” over the past week, according to research by the Centre for Countering Digital Hate (CCDH), a disinformation watchdog. Imran Ahmed, the CCDH chief executive, said the globalist conspiracy theory was rooted in antisemitic tropes but had morphed to encompass the beliefs of different groups who believe global elites are controlling world events, such as white supremacists promoting an anti-immigrant “great replacement” conspiracy theory, and QAnon, the extremist movement with roots in the US. “Rishi Sunak’s elevation to prime minister has become the latest flashpoint that antisemitic conspiracy theorists use to promote their hate-filled agenda by taking advantage of trending topics on social media to maximise visibility,” Ahmed said. Sunder Katwala, the director of the thinktank British Future, said the globalist tag echoed old antisemitic tropes but was now being used against non-Jewish and Jewish figures. “Some Twitter users will copy the slogans without thinking much but people could also could desist from ‘globalist plot’ and, if they wanted, choose to make coherent and substantive arguments against liberal pro-globalisation policies in a better way if they really didn’t want to echo antisemitic tropes,” he said. The CCDH’s research, which used the Twitter analytics tool Brandwatch, found that highly viewed tweets targeting Sunak included some claiming that moves to oust loyalists to Liz Truss amounted to a “globalist coup” and others claiming that the new prime minister has “zero loyalty” to the UK. The tweets spiked on the Sunday evening when Johnson pulled out of the Tory leadership race and it became clear that the former chancellor was likely to succeed Truss. Last week, John Mann, the former Labour MP who is now a non-affiliated peer and the government’s independent adviser on antisemitism, called for GB News to sack Farage and another of its presenters, Dan Wootton, if they did not rescind their language about “globalists”. A GB News spokesperson said: “GB News abhors antisemitism and all other forms of hate and racism. Nigel and Dan were referring to the Oxford English Dictionary definition of the term globalist, meaning ‘advocating the operation or planning of economic and foreign policy on a global basis’. They were in no sense referring to a racial, ethnic or cultural group.”