The fifth and final season of The Wire -- the best American TV show ever broadcast, according to Slate editor Jacob Weisberg -- will make its British debut on July 21. Rather surprisingly, it will be shown on the little-known cable channel FX. The sad truth is that The Wire has never been a ratings success. When the series was originally broadcast in America it was rarely seen by more than four-and-a-half million people.

I’ve only recently started watching it, having bought season one on DVD, and can’t say I’m completely mesmerized. Set in the city of Baltimore, it is certainly well-written and no one could doubt its authenticity. The show’s creator, David Simon, worked as a reporter at the Baltimore Sun for twelve years and his writing partner, Ed Burns, is a twenty-year veteran of the Baltimore Police Department. The Wire’s depiction of life in a failing American city -- and the African-American experience, in particular -- is surely the most accurate there has ever been on television.

Yet The Wire doesn’t just strive to be more realistic than shows like CSI and Law and Order. Simon has employed some of America’s best crime novelists to write individual episodes, including Dennis Lehane, Richard Price and George Pelacanos, and his literary ambitions easily outstrip those of his competitors. Last year, he told The New Yorker that the writing staff had “ripped off” authors such as Sophocles, Aeschylus and Euripides. “We’ve basically taken the idea of Greek tragedy and applied it to the modern city-state,” he said. That, in turn, points to another distinctive feature of The Wire: It is animated by Simon’s abiding anger about the destructive effect of what he calls “raw, unencumbered capitalism”.

The upshot is that each season of The Wire is less like a television show than an epic novel, with a sprawling cast of characters, a dense, interlocking plot, and an underlying moral vision. The problem is, it is more like the work of an early 20th Century American novelist -- Upton Sinclair, for instance -- than a 19th Century English novelist. David Simon is so intent on venting his rage about the collapse of America’s social fabric, he leaves out all the lowbrow devices that make the greatest works of social realism so entertaining. Charles Dickens, for instance, included a good deal of mystery and romance in his novels, not to mention comedy, horror and suspense. Without such cheap tricks, The Wire can often be quite heavy going.

Don’t get me wrong. Once you have watched four or five episodes of The Wire, you start to care deeply about the fate of the characters and I’m looking forward to seasons two to five. But the best American TV shows, like The Shield and Damages, manage to combine serious themes with a cornucopia of cheap tricks -- and there’s nothing wrong with that.