In an Islington square overlooked by regiments of tall Georgian houses, taking a break before he returns to the Almeida Theatre’s nearby rehersal space, Elliot Levey considers where it all went wrong for Judaism. Or, more specifically, Jewish theology.

“We’ve joined this fantastic new synagogue,” says the actor who is working on a new production of Chekhov’s Three Sisters. He’s probably best known for the TV show Da Vinci’s Demons, though theatre audiences will know him from eye catching productions at the National Theatre and his Burleigh, a blood-chilling presence in the Almeida’s recent production of Mary Stuart.

“I’m like a new Jew,” he adds breezily.

By “we” he means his three “very Jewish” teenage sons and his slightly less Jewish wife Emma Loach, a commissioning editor of documentaries at the BBC.

She is also the daughter of film director Ken Loach who is almost as well known for his support of Palestinians and for being one of Israel’s most strident critics as he is for his films. There must be some tricky dinner conversations on that subject, what with Levey being an emphatic supporter of Israel, if not its policies, though more of that later.

“I’m a member of Finchley Progressive,” continues Levey. “They are politically sound, their theology is brilliant, and they basically dispense with Talmudic nonsense and go back to prophetic Judaism. They go to the source, which is the Tanach. I couldn’t care less what the great sages of old thought about the text that we can all read. Should we probably not pay so much attention to what rabbis starved of secular literature thought of it?”

Levey speaks about Judaism with the confidence of having lived an Orthodox life.

“I had an intensely Jewish upbringing”, he told the JC a few years ago when he was playing French revolutionary zealot Robespierre, in Bruchner’s Danton’s Death. Though his parents ran a largely secular household in Leeds, he went to a “very Orthodox cheder” where he was “taught by Yiddish speakers”. At 13 he was leading services in Clifton College’s Jewish house, Polack’s. Now aged 45, he’s embracing progressive Judaism with similar zeal.

“I went to an Orthodox barmitzvah recently and this rabbi was doing Noach — Noah and the rainbow — and then the rabbi gave his speech about the meaning. He went through every permutation of what the rainbow represents except the one thing it means in the modern world — gay rights and equality. It was outrageously telling,” he says with a simmering anger.

It is a tricky time for a man such as Levey who sees so much wrong in the two belief systems with which he most strongly identifies — one cultural, the other political. If progressive Judaism has brought some peace to his Jewish side, his political side remains highly conflicted. “I am and always have been not just a member of the Labour Party but willing, hoping and campaigning for a leadership like this leadership, and one that has this leadership’s policies. So I’m in complicated territory because the leader happens to be a man who has been accused of certain things and is absolutely guilty of them. I have defended him, too much.”

For Levey, the mural incident was one of a series of what might be called last straws. Corbyn’s relationship with Iranian state television, on which he declared his “hand of Israel” theory in respect of a terror attack in Egypt, is another.

And if Levey needed a third last straw it was when he was on a march with the Stop the War Coalition for which Corbyn was chair. Levey had been “marching” and chatting “in solidarity” with the man next to him when Levey’s fellow marcher began chanting: “From the river to the sea, Palestine will be free.”

“Everyone else started joining in. So they were calling for the destruction of a country, and genocide,” says Levey. “I went, ‘Goodbye Stop the War coalition’.”

Levey also has things to say about Ken Livingstone who “had been caught out by that unspeakable piece of quasi-history by Lenni Brenner— one of our own, of course — who wrote the most abysmal history hack job. It’s like quoting from David Irving. One’s on the left. One’s on the right.”

Meanwhile Corbyn “has Seamus Milne whispering in his ear”, says Levey who compares Labour’s Director of Strategy and Communications to Lord Burleigh, the hardliner Levey played in Schiller’s Mary Stuart who whispered in favour of Mary’s execution.

Yet the elephant in the, erm, garden square today is Levey’s father-in-law Loach, one of Corbyn’s fiercest defenders. It’s tricky.

“I definitely don’t want to get into this territory,” says Levey. “It’s too close.” Okay. But might we draw our own conclusions about Levey’s opinion about his father-in-law’s politics, especially about Israel, Corbyn and Labour’s relationship with Jews?

“Yes, you can,” he says, although like everything that seems simple on Twitter and the shouty exchanges between pro-Israel and pro-Palestinian campaigners, it is actually more complicated than you might think.

“Ken is an extraordinary brain, an extraordinary man and an absolutely wonderful father-in-law,” says Levey. “He goes with us to shul and has spoken there. And he has three very Jewish grandchildren. Sam, Benjamin and Jacob are Jewish boys.”

Rehearsals will start again soon and we have spoken about politics much more than we have about acting. Though when we do Levey is really interesting on how naturalism as an acting style is developing.

In this current show, which is directed by Rebecca Frecknall and features Patsy Ferran (both have just won Olivier Awards for their work on the Almeida production of Tennessee Williams’s Summer and Smoke) Levey trills about the quality of the acting being delivered by his fellow cast members, though in a way that is more than just promotional puff.

He says it is the sort of acting that is so natural it can be hard to know when they’ve started rehearsing. “I think ,‘Is this happening? Yes, it is. And now it’s my line.’”

Levey plays the teacher Kulyigin, victim of his loveless marriage to the much younger Masha (Pearl Chanda). He is not the most likeable of characters. But then Levey seems to be a specialist in unlikeable characters.

“It’s often true,” he admits “And there is a splinter in my mind, that whenever I’m cast in one of those slimy politico roles, I go ‘is there a subconscious, erm…” The pause is because he doesn’t want to say what he’s about to say. “Look, I know antisemitism is current, and I’m really terrified of screaming anti-semitism…” Then he tries a different tack.

“I’m not suggesting to all those people who employed me that they are antisemitic. But however progressive the writers or the director’s intentions, there is obviously something…” He pauses again before finding the word: “unlikeable about my bloody face.”

There is, he adds “something fantastically entrenched in Western psyche which has this really strange relationship with the Jew and their Jews. It is just like being obsessed with class in the way that people can be disgusted with their own innate snobbery. Antisemitism works in a similar way.”

It appears that we have gone off the topic of acting again. “Ah,” says Levey. “That’s because we’re Jews.”

Three Sisters opens at the Almeida Theatre next week