"Roman Polanski?" someone said to me yesterday afternoon. "Well, he's not as bad as Jimmy Savile, is he?"
That is like a red rag to a bull.
Was Jack The Ripper not as bad as Adolf Hitler because he did not kill as many people? You could even argue Adolf Hitler was a morally better person than the Jack The Ripper because, as far as I am aware, Hitler did not personally kill anyone during the Second World War.
It is a pointless argument.
Jimmy Savile had-it-off with more under-age girls than Roman Polanski and was apparently at-it for 50 years. Roman Polanski was only prosecuted over one girl.
But the truth is you cannot compare evil.
Most things are grey. But some things are black and white and incomparable.
I had a conversation with two other men a couple of days ago and which I started to write a blog about the next day but which I aborted because it was too dangerous...
One man was involved in the comedy business. The other had been involved in the music business. We had got talking about Gary Glitter.
When the Spice Girls' movie Spice World was made, it included a big musical routine involving Gary Glitter. Very shortly before the film's release, he was arrested on sex charges. He was cut out of the film because (quite rightly) it was thought to be dodgy given the movie's target audience.
But now, in many places, several years later, his music is, in effect, banned from being played because the act of playing it - and saying his very name in the introduction - is thought to be in bad taste.
The conversation I had with the other two men revolved around Art v Scum.
Just because someone is scum does not mean they cannot create Art.
Just because they have been rightly arrested, prosecuted and imprisoned for an act of evil does not lessen the level of any Art they may have created.
I am sure all sorts of artists over the centuries have committed all sorts of morally and criminally heinous acts. But that does not mean we should not appreciate their art.
You may see where this is going and why I abandoned writing this particular blog a couple of days ago. Just by discussing it I might seem to be lessening my dislike of what the scum did. Which is not the case. But it is a danger.
Just because Gary Glitter is scum does not mean he did not create some very good pop music. Perhaps it was not high art. But it was good pop music. The fact that he was imprisoned for having pornographic images of children in Britain and committing sex crimes in Vietnam does not mean his records should be banned.
There is the fact that, if you buy his records, he will receive royalties. That is a problem, but does not affect the theoretical discussion.
Clearer examples are actors Wilfred Brambell and Leslie Grantham.
Homosexuality was stupidly illegal in the UK until 1967. In 1962, Wilfred Brambell (old man Steptoe in the BBC TV comedy series Steptoe and Son) was arrested in a Shepherd's Bush toilet for "persistently importuning", though he got a conditional discharge. Ooh missus. He died in 1985. In 2012, he was accused of abusing two boys aged aged 12-13 backstage at the Jersey Opera House in the 1970s. One of the boys was from the Haut de la Garenne children's home, which is now surrounded by very seedy claims of child abuse, murder and torture (and which Jimmy Savile visited, though this is strangely under-played in newspaper reports).
Actor Leslie Grantham - who famously played 'Dirty Den' in BBC TV's EastEnders - is a convicted murderer. In 1966, he shot and killed a German taxi driver in Osnabrück. He was convicted of murder, sentenced to life imprisonment and served ten years in jail.
Wilfred Brambell's presumed sexual sleaziness and Leslie Grantham's actual imprisonment for killing someone does not mean the BBC should never repeat Steptoe and Son nor old episodes of EastEnders, nor that it would be morally reprehensible to watch the Beatles' movie A Hard Day's Night because Wilfred Brambell plays a prominent role in it.
It does not mean that Wilfred Brambell and Leslie Grantham's undoubtedly high acting skills should not be appreciated.
A chum of mine was recently compiling a history of glam rock for a BBC programme and was told he could not include Gary Glitter. That is a bit like not including the Rolling Stones in a history of 1960s British rock music or not including Jimmy Savile in a history of BBC disc jockeys.
Which brings us to Roman Polanski.
As anyone who reads my daily blog knows, I think he is scum and (figuratively speaking) his balls should be cut off and he should be thrown into a bottomless pit of dung for eternity.
He allegedly raped and buggered a 13-year-old girl.
End of.
The defence "She was not that innocent" is no defence.
In January next year, the British Film Institute starts a two-month "tribute" to Roman Polanski at the National Film Theatre in London.
I have no problem with that. I might even go to some of the movie screenings.
Dance of the Vampires, Rosemary's Baby and Macbeth are brilliant films. Chinatown and Tess are very good - although I have also had the misfortune to sit through the unspeakably awful Pirates.
As a film-maker, Roman Polanski deserves a tribute. As a criminal on the run from justice, he deserves to be arrested and imprisoned.
Art is often created by people who are scum.