There's something about a Harry. It's a geezer name for diamond blokes – as both the prince of that name and a certain football manager have been reminding us all week. The slang is significant. Harry is an affectionate diminutive of Henry. Pet names don't just shape the way we think about people; they appear to shape the way the name-holders behave.

The official name of Prince Harry, who qualified last week to pilot an Apache attack helicopter, is Prince Henry Charles Albert David of Wales. Henry James Redknapp, unlike Prince Harry, was designated by his full name in the courtroom where he was acquitted of tax dodging, though football fans chanting their support at recent Spurs matches have preferred the more demotic Harry.

Harry was the third most popular boy's name in the list of parental choices last year. The more formal Henry was a lot lower down. But Harrys are vernacular sorts of chaps. "There's no way I'm going to put myself through Sandhurst and then sit on my arse back home while my boys are out fighting for their country," His Royal Highness opined when his regiment was sent to Iraq. He responded by taking the rigorous Apache combat course that will destine him for Afghanistan, in contrast to the search and rescue helicopter training of his big brother, William.

Harry Redknapp equally has never been one for the soft option. In several brushes with controversy over his decade as a manager he's coped throughout with a laugh and a wink. He even had some of the jury repeatedly chuckling at his laddish comments. "He would say that, he's an Arsenal supporter," he quipped of one barrister.

But even if he had been found guilty, many would still have regarded him as a loveable rascal. The comedian Ken Dodd, who was similarly acquitted of tax evasion, still tells nudge-and-wink gags mocking the Inland Revenue 30 years on and his audiences love it. Nor have Prince Harry's various brushes with the law, smoking cannabis and under-age drinking, diminished public affection – not even when he went to a fancy dress party sporting a swastika armband.

Harry Potter has almost made the name respectable, but there is a roguishness about a Harry that Shakespeare understood when he charted the transition from prince to king in Henry V. His hero left behind Harry and Hal as responsibility beckoned. The reverse is clear in the transmutation of Dr Matthew Hall into Harry Hill when the GP exchanged intestinal medicine for burping comedy.

Harry is more affably plebeian. Think Harry Ramsden, the personification of that most working class of British staples, fish and chips. But there is also Flash Harry, an "an ostentatious, loudly-dressed, and usually ill-mannered man", according to the OED. Harrys were, in the 19th century, also the name of inferior playing cards of the second quality.

But everyone loved them, just as 100 years on they loved Clint Eastwood, the outcast cop and avenging angel in Don Siegel's classic vigilante film Dirty Harry. "You don't assign him to murder cases... You just turn him loose," the movie posters read.

The public love Harry Redknapp's Houdini ability to get out of scrapes as well as his intuitive ability to get his players to play football beautifully. He represents the instincts and aspirations of the common man, for whom sport is the only respectable vehicle for a peculiar national fervour born more from a sense of hope than expectation. The game is afoot: follow your spirit, and upon this charge cry, "God for Harry, England and St George".

It can, of course, end in tears. In Harry's Game, the Eighties TV series about the British Army and the IRA, the eponymous hero gets shot dead in the end. That's the risk you take, being a Harry.