It’s nine in the morning on the East Coast when I Skype with Deborah Lipstadt, the 71-year-old American professor of modern Jewish history and the Holocaust. She has already been to the gym and is decidedly perky, ready to dive straight into the less than cheery subject that has been preoccupying her for the past few years: the rise of contemporary antisemitism in the US, Europe and beyond.

Lipstadt came to worldwide attention when she was sued for libel by David Irving after she described him, in a 1996 book on the subject published by Penguin, as “one of the most dangerous spokespersons for Holocaust denial” . Although the trial lasted just a few months and Lipstadt was resoundingly victorious, the episode dragged on for six years –– a period that she says was incredibly stressful and disruptive.

Her subsequent book about the fight for historical truth was made into a film, Denial, starring Rachel Weisz and Timothy Spall.

“How did the whole trial experience change me,” she asks rhetorically in a broad New York accent. “I’m still the same person with the same ideas but it’s given me a much bigger megaphone — when I talk, more people listen. Consequently, I am more careful about what I say. If you want to be heard, don’t yell.”

And so she’s back with a new book, this time tackling the whole, thorny topic of antisemitism.

What made her write about this subject? “I didn’t want to write it,” she exclaims. “Many of the protests during the Gaza war had signs of overt antisemitism to a degree we hadn’t seen before, and an intensity we hadn’t see before. So I wrote this article in the New York Times and it got a lot of attention. My agent wrote me a note, saying: ‘Where’s the book proposal?’ So I said, ‘Book proposal? I don’t want to spend my time writing a book on this. I just don’t want to do it.’” But she was eventually persuaded and so she set about thinking how best to present the growing body of evidence. “Little did I dream that, in the subsequent three years, it would become such a major issue, that it would have this urgency.”

Lipstadt is warm, high-spirited and eloquent — her whole professional life had been dedicated to research and teaching — and she talks a mile a minute. She’s funny, too. “So I’d started to write it,” she recounts, “but it was very boring, it had no juice — j.u.i.c.e, not Jews!”

A friend suggested that she format the material as a series of letters to make it more accessible. So, fictitious Jewish student Abigail and non-Jewish academic Joe write to her with their experiences and questions, which she then unpicks in a considered and thoughtful way. “I’m very anxious for it to reach a wider audience; I didn’t want to write for just ten people,” she says.

What were the incidents that concerned her most? “First of all, everything’s that’s gone on in Britain; second of all in the US with Trump and the rise, or the invigoration, of the far right; [Hungarian leader]Viktor Orban; Poland’s Holocaust law.” And the list goes on — that was the biggest problem, knowing when to put down her pen. Every day a new incident of antisemitism would come to light.

Lipstadt’s father left Weimar Germany in 1927; her mother was born in Canada, and the couple met at a New York synagogue. Her home in Queen’s was Orthodox but “very much involved in the world” — there was music and books and culture. A transformative trip to Israel in the late 1960s, where she saw survivors everywhere, made her much more conscious of the Holocaust and set her on the path of studying — and later teaching — Jewish history, first at the University of Washington, then UCLA and, since 1993, at Emory University in Atlanta, Georgia. A meticulous researcher, she drafted and redrafted the new book (some 30 times, she admits, and asked friends for second opinions) in the search for balance.

“The book isn’t a cri de coeur; it’s not a vendetta — I tried to write in a measured way. I really didn’t want to sound hysterical, over the top. We have a problem so let’s try to understand it, how does it manifest itself, how does it connect with other things?”

So did she learn anything unexpected along the way? Surely someone who studies and teaches the Holocaust is already well versed in all manifestations of antisemitism.

“I learnt about the nuances of antisemitism — and it sharpened my focus. Right-wing antisemitism I understood, but I never grasped as fully as I do now the nature of antisemitism among progressives, those who consider themselves on the left.”

She is referring to Labour’s Jeremy Corbyn, his reluctance to stamp out antisemitism in his party and his subsequent rift with the Jewish community. “When people on the left look at Jews, they see white people and people of privilege. Ipso facto, they cannot be people who suffer from prejudice — because they have power.”

Lipstadt is highly critical of Corbyn’s actions as a back-bencher, such as those occasions when he met members of Hamas in Parliament and said that Zionists have no sense of irony, something for which he is yet to apologise. She gives him short shrift: “I don’t know what’s in his heart but at the very best it’s a willingness to condone antisemitism, a willingness to look the other way, a failure to take it seriously.”

So should we always call out antisemitism whenever we see it? Lipstadt’s answer is unexpected — yes, but she urges caution, too. “This is what I say in the book: it’s a battle and we have to think strategically, so sometimes we have to think and keep quiet and sometimes we have to yell to the heavens. Jeremy Corbyn is a potential prime minister — we don’t keep quiet.”

Lipstadt says that the book itself is not a battle call but an attempt to decipher what’s behind the rise of antisemitism and what can be done about it: “One of the things I want to do is help people to understand it, that antisemitism comes in many forms and not simply [from] Nazi extremists… we need to define it, help people put their hands around it and also to give them the gumption to speak out.”

She also counsels that it’s important to be aware of the way that language is used when talking about Israel, Jews and antisemitism. There’s space, she says, for free speech and reproof, as long as critics do not resort to antisemitic tropes and stereotypes. “If you’re going to speak out as a critic you have to work hard. You don’t want to play into the hands of people who are racist, or truly antisemitic. You want to be heard, and not dismissed.”

Her passion for her topic and energy in delivering her message are infectious and it’s heartening that, in the end, she decided to conclude the book on a hopeful note.

“My plea is that antisemitism should not be the leitmotif, the raison d’être, the chorus of our Jewish identity. We should never be Jews because of antisemitism, we should identifying as Jews despite it.”

Since the Irving trial in 2000, she has continued teaching — “being in the classroom keeps me grounded” — writing for the likes of the Atlantic and the New York Times and has no plans to retire. Lipstadt describes herself as optimistic and positive, qualities much needed when delving into the painful history of the Holocaust — as well as waging war on strident Holocaust deniers. “I rejoice in my Jewish identity, I rejoice in my womanhood, I love to laugh, I have a pretty good sense of humour,” she says. “Has the subject begun to weigh on me? No, because then I couldn’t do my work…”

She’s preparing to come to the UK to speak at JW3, the How To Academy, among other media engagements and school talks. “I would say I’m in England a minimum three times a year, it’s like a second home. In fact, I’ll show you…” there’s a rustling of papers on her desk. “Just in case you were wondering –– I have my oyster card!”

Our time is nearly up and I feel we’ve only scratched the surface of contemporary antisemitism and where it’s heading. Just as I’m about to ask another question she realises that she is due in class. “Ok, I gotta run teach!” And she does.

‘Antisemitism, Here and Now’, by Deborah Lipstadt, is published by Scribe

She will be speaking at JW3 on February 9