Prof Goodman is himself a deeply-tolerant man, coming from a Jewishly-diverse background.

His late grandfather, Paul Goodman, although an Ashkenazi immigrant from Estonia, helped the late Haham Moses Gaster run the Sephardi Spanish and Portuguese Congregation.

In fact, Prof Goodman is following in the scholarly footsteps of his grandfather who wrote A History of the Jews in 1911.

When Paul arrived from Estonia in the 1890s at the age of 16, he was hunting for a job. In 1901, he was appointed assistant secretary to the S&P and rapidly became its secretary.

Hammersmith-born Prof Goodman moved with his family to Burnham-on-Crouch in Essex as a child.

He said: “My family practised little beyond a Sabbath-eve dinner each Friday, an annual family seder and occasional attendance at Bevis Marks Synagogue.”

Prof Goodman attended the public school of Rugby, hardly the most likely place for a Jewish identity revival.

But there he met with other Jewish boys and received Jewish education on Sundays.

He said: “I became more interested in Judaism as a teenager, but was not yet exceptionally observant for obvious reasons.”

Before taking up his place at Oxford University to read classics, Prof Goodman spent nine months at Jerusalem’s Hebrew University where he became religiously observant. He never went through the yeshiva system, but studied Talmud informally.

He said: “My family were very tolerant of this change in my lifestyle. My decision as a teenager to adopt a more Orthodox lifestyle was a form of mild rebellion, with which the rest of the family coped with admirable patience.”

He added: “It is probably significant that I have found a home in the Oxford Jewish Congregation, which is unusual in the UK for housing Progressive and Masorti, as well as Orthodox services within a single community.”

His latest book owes its origin to his doctoral thesis at Oxford on the subject of ‘The State and Society in Roman Galilee’.

After a period lecturing on Roman and Greek history at Birmingham University, Prof Goodman returned to teach at Oxford University in 1986.

Until seven years ago, he commuted from Oxford to Birmingham, where his wife Sarah had become a partner in a law firm.

In Oxford, Prof Goodman taught in the theology and religion faculty about the varieties of Judaism in late second Temple period.

He said: “I was allowed to teach just one course which actually used my expertise. I published a number of articles and a book of collected essays on the subject 10 years ago.

“I thought it would be a good idea to try to bring it all together into a single narrative. Some of the ideas I had been trying out are slightly different from those in the main textbooks.”

Prof Goodman’s original findings included the theory that, unlike the traditional Christian-based view that the Pharisees were the rabbis, they were actually two distinct groups.

He said: “When the Mishna talks about the Pharisees, it doesn’t talk about them as being themselves, the talmudei chachamim (the sages).

“Pharisees’ disagreements with the Sadducees are talked about from the outside. It was the Christian scholar Jerome who, in the fourth century, described rabbinic Jews as the Pharisees.”

The rabbis, Prof Goodman said, were distinct from the Pharisees in that they were more learned and received their knowledge orally from their teachers.

He now finds it fascinating that today so many charedim spend their lives poring over the words of the ancient rabbis who wrote the Mishna and Talmud.

He said: “It is entirely in the spirit of the rabbinic movement. My job as an academic is to try to understand what people believed, when they believed it and how they acted.”

While the term ‘charedim’ has only been in general use to describe ultra-Orthodox Jews for the last few decades, Prof Goodman traces it back to the Hungarian Jewish reaction to the 18th century Enlightenment.

Another of his original theories is that it was not, as generally thought, the Essenes who wrote the Dead Sea Scrolls, but another group called Yachad.

A History of Judaism chronicles the vast variety of different Jewish groups which have developed since the second Temple period.

He says: “I wanted to bring out the extent of the variety within Judaism during all periods.

“The classic notion was that there were lots of types of Judaism in the second Temple period, including the Pharisees, Sadducees and Essenes and that everybody then became rabbinic when the second Temple was destroyed and that then they only started disagreeing again in the modern era.

“I wanted to bring across to what extent there were always lots of types of Judaism.”

He wrote: “Judaism has a rich history of rifts. But, despite the rhetoric used against opponents by religious enthusiasts, religiously motivated violence between Jews was not common.

“Nothing within Judaism was quite like the Christian wars of religion in Europe in the modern period or the deep hostility between Sunni and Shia in Islam.”

He said: “History is news written on a large scale. It is much easier to write a history of rifts, arguments and broigus.

“It is very tempting to go through all the arguments of the major aspect of disputes in Judaism.

“Jews, over the generations, have had very strikingly different views on practice and theology. They argue with each other, don’t necessarily give in to each other, but they eventually rub along with each other.

“It is a grumbling type of set-up. They do not settle down into intense opposition. You have occasional flare-ups and then an extraordinary extent of cross-communal co-operation.

“If you look back over the history of Judaism, it is very remarkable the way that any one issue can become crucial for a generation.

“A couple of generations later, people can’t remember what they were arguing about. It’s not that the issue has been solved, just that people decide to just live their religion.

“Judaism has developed. Judaism now is not quite the same as what Abraham and Moses were getting up to. Things are different.”

So how does Prof Goodman see present-day Judaism and what are his predictions for the future?

He said: “There are clear differences between countries now. In the UK, the Orthodox have reacted against the Reform and, in Israel, there are arguments between the secular and religious.

“When communities are in the middle of major arguments they think it’s always been like that.

“One of the advantages of getting a historical perspective is to see it hasn’t always been like that and to understand the reasons why there are flare-ups at particular times.

“There is a lot more antagonism worldwide between groups than there has been in other periods, but there is no particular reason to suppose they will last.”

An advantage today, he says, is “that the notion of toleration as a virtue in itself is very widespread in Western society. Saying I’m being tolerant sounds good.

“There might be more toleration now for reasons very different from in earlier periods.”

He concluded: “I don’t know what’s going to happen next. It is very striking that many young Jews want to go to one extreme or the other.

“They either drop out entirely or go for one of the many different types of forms of Judaism that have been created.

“Or they opt for the charedi notion of going back into what they think of as the original form of Judaism, but which is in many respects 18th century.

“You can see the attraction. I am the last person, knowing where I started from, to think that any of these responses are illogical.”

A History of Judaism is published by Allen Lane, priced £30.