Jews were not always as middle-class and law-abiding as they are today.
A notorious group called the Bessarabian Tigers controlled the Whitechapel area of London's East End just before the First World War.
And a few years later a new name emerged as Alfie Solomons and his brother Harry, aided by an Italian gang run by Darby Sabini, controlled north London and terrorised race courses around the country.
Such villains were the inspiration behind the TV drama Peaky Blinders - the story of a violent Birmingham gang named after the caps they wore.
The second series, currently showing on BBC2, sees them expanding their operations to London and coming into contact with the Jewish gangs.
Writer Steven Knight says that he saw his role as "holding hands with history" rather than slavishly adhering to events. But his research has revealed much about the Solomons brothers who operated from Camden Town.
Knight explains: "People would flood to the race tracks. They would be carrying a lot of cash and might be a bit drunk so they would be easy prey for straightforward robbery. A lot of the bookies were Jewish and, as they became the target for people stealing money from them, they got themselves protection from the Jewish gangsters. One gang would be protecting, while another would be attacking." This, he says, is how the Alfie Solomons' gang became both famed and feared. "He would be both attacking and protecting on the race courses. His gang became a formidable force, and inevitably they came into contact with powerful Birmingham gangs. There was a very famous incident at Bath racecourse which became known as the Battle of Bath as the gangs came to blows. There was a big court case against Harry Solomons who was arrested for pulling a gun on a policeman."
Knight adds that there were other gangs around at the time but the names Darby Sabini and Alfie Solomons keep recurring in court records as immigrant gangs rose to control the betting and protection rackets.
Knight says: "It was the same in London as it was in New York. There was an Italian quarter and a Jewish quarter and immigrants would stick together as immigrants do. Some of the locals would see the gangsters as offering protection against outsiders and that made them heroes in some circles."
Although gang activity would have been obvious to those living in the local working class neighbourhoods their actions were under-reported in the press.
Knight says: "Newspapers at the time lacked a tabloid sensibility. They tended to concentrate on the empire and on world affairs. Fights between gangs of working class men were not considered newsworthy unless shots were fired and people killed."
For that reason, the depiction of Alfie Solomons, played by Tom Hardy in Peaky Blinders, is based on legend.
"The reality is difficult to portray but there were snapshots. But when you have an actor of the standard of Tom Hardy you want to make the most of him so we have portrayed him as funny but with an edgy character."
With gun crime rife, as soldiers brought their weapons home from the front, many gangs thrived. But few were as well remembered as Solomons.
Knight say: "The Jewish gangs of the East End would have been just as famous but for some reason history seems to have remembered Alfie Solomons. I don't know why. Maybe, he was prosecuted more often."
Whatever the reason, a whole new generation are discovering that life on the streets for Jews in the 1920s was a lot more colourful than many of us would have imagined.