I fear more laughed with Alf Garnett than at him

Not that Mitchell's performance, or Speight's writing, was anything less than inspired. It was, after all, a fantastically accurate portrayal of a certain kind of bloke who was brimful of a particular brand of xenophobic, bad tempered opinion. But while many of us were laughing at him, many others were laughing with him.

I once put this to Mitchell. Clearly, I was not the first. "Look," he said, not bothering to hide his irritation, "you can't help it if people are idiots. I had a bloke come up to me one day and say, 'I love that show of yours Alf, especially when you have a go at the coons.' I said, 'Actually, we're having a go at bastards like you.'"

But the problem with Mitchell's, no doubt sincere, riposte, is that there isn't much point in having a go at the bastards if the bastards simply think you're having a go at someone else. Whoever comedy writers, actors and comedians have in mind as their target is not the point. The point is, who is laughing?

When, in the 1960s, the American, Jewish, professionally offensive comedian Lenny Bruce directed a tirade of offensive racist names at his shocked audience, the words eventually started to lose their meaning, and with it their power. And, with that, the power of the people who used them.

It was a brilliant blunting of a bigot's favourite weapon, words. But take Bruce's opposite. Take (not my wife), a comedian such as Bernard Manning. Manning was a stand-up who could deliver a line of comedy with the finesse, rhythm and timing of a Cole Porter song. Though not the words, which he used like a bully. He often liked to point out a black face in the largely white audiences of the working mens clubs where he used to perform. He would ask his victim where he was from. If the answer was England, Manning would say, "Where are you really from?" And then: "Just because a donkey's born in a stable, it doesn't make it a horse." This usually went down well with the white faces. Alf would have laughed.

There was one Bernard Manning joke that started, "My father died in a concentration camp." Now, any Jew who hears a man like that begin a joke this way, knows that there is trouble ahead. But on this occasion, they would have been wrong. "Fell out of his watch tower," went the punch-line.

I laughed a lot when I heard him tell it - partly out of relief over the joke's target (not Jews); partly at the absurdity, sustained even for one short second, that Manning's dad was a Jewish Holocaust victim, but mainly at the beautifully timed switch between where the joke was seemingly headed and its final unexpected destination. Good one.

Having written the above, it seemed a good idea to check whether Alf does indeed have a Twitter presence. And although the already much-missed Mitchell died a week ago, it turns out that not only did Alf Garnett have a Twitter account, he still does.

Obviously, it has nothing to do with Mitchell. But it does have a picture of the actor in Alf Garnett mode. Behind him is a Union flag. Next to the picture are the words "Love my country and loathe those that use and harm it." Scroll down and there is a series of anti-Muslim postings. Dogs defecating on prayer-mats, that kind of thing.

It's probably worth remembering that there was a tiny flame of humanity in Alf that Mitchell, himself a most humane man as well as a terrific stage and classical actor, always somehow managed to keep alive in Garnett. Because of this Alf was, deep down - very deep down - likeable. So it's a fair bet that the original Alf would have railed against this hateful Twitter imposter.

Yet if, in the final reckoning, satire and parody are to be judged not only by who is joking but who is laughing, then, as the Twitter Alf Garnett would seem to prove, the comedy directed at bigotry can often miss its target.