Suspended Labour MP Chris Williamson campaigned repeatedly in support of a Spanish author and military colonel now dogged over allegations his book is antisemitic.

Mr Williamson, who had the party whip withdrawn in February after a "pattern of behaviour" of controversial interventions in Labour's antisemitism crisis, raised the case of Pedro Baños in the House of Commons in December, claiming it was a “democratic outrage” he had not been appointed Spain’s Director of National Security.

In a parliamentary question, Mr Williamson said Mr Banos had been subjected to the same “smear campaign” as Jeremy Corbyn from an organisation named Integrity Initiative and demanded an independent inquiry.

He even wrote to the Spanish Prime Minister alleging “British interference” in Mr Baños' appointment.

Mr Williamson's campaigning was approvingly reported by pro-Corbyn websites The Canary and Novara Media.

The Canary carried a photo of Mr Williamson at the door of Integrity Initiative’s Scottish office – while in the far-left Morning Star newspaper, he was quoted alleging a Tory MP was also behind the campaign to stop Mr Baños getting the job.

Col Baños’ book How They Rule the World was published in English by Ebury Press, a division of Penguin Random House in April.

It makes several references to the Rothschild family, including a passage accusing the banking family of holding “gigantic” economic power and influence which has “led to multiple speculations about their capacity to intervene in key global decisions”.

The Spanish edition of the book contains three references to the Rothschilds, including a section that compares their wealth with other rich families, and concludes: “It is clear that [the Rothschilds’] economic power is gigantic.

"As is their ability to influence in all senses, an aspect that, when considering their traditional distance from the media spotlight, has led to multiple speculations about their capacity to intervene in key global decisions.”

The front cover featured an image of octopus tentacles, which have long been associated with antisemitic propaganda.

The German edition changed the cover image to a globe of the world following criticism from the group Judisches Forum – who campaign against antisemitism there.

Jeremy Duns – the British spy author – discovered that the Rothschild references had been removed from the English translation of the book.

Penguin later confirmed that Mr Duns’s critique had prompted a review of Col Baños’s work, saying it was aware of “serious concerns”.

It concluded that, while the author expressed “robust opinions about geo-strategies and geopolitics… he does not in our opinion express views in this publication, including in the parts omitted, that are antisemitic”.

In radio and TV interviews, Col Baños has referred to the power of George Soros, and has also discussed Satanic forces and families controlling the world.

Col Baños has also received support from other pro-Corbyn figures including author Aaron Bastani.

Writing on Twitter on Wednesday, the Community Security Trust’s Dave Rich said: "Maybe Williamson and Bastani didn't know that Banos believes the Rothschilds run the world. Maybe they knew but didn't think it mattered.

"Who knows. But it's odd, isn't it, how often anti-racists of the British left inadvertently find themselves defending antisemites?”