WHOEVER said that mankind could not tolerate very much reality did not live to witness the 21st century. Reality, like monogamy, is a concept which has seen a dramatic reversal in its fortunes in recent years. For generations it was regarded as fantasy's plainer and less interesting sister.

Now everyone is in love with reality, and will pay good money just for a glimpse of it.

For example, there is talk of a musical based on David Blunkett's sex life. No one seems to think this strange. No one has raised the guide dog difficulty, although you would have thought that the animal welfare people would have been on it like a light.

What did that poor dog get to see? We think we should be told; and very shortly we shall be told. But no one has considered the dog question yet. The only stumbling block acknowledged is the thorny question: who has the nerve to play an all-singing, alldancing version of Kimberley Quinn?

In Dublin at the moment the musical I, Keano is playing to enthusiastic audiences.

Although it is based on the daring deeds of a legendary hero . . . in a skirt, always a good start . . . this legendary hero comes from Youghal and lives in Manchester. Roy Keane has intimated that he's unlikely to go and see I, Keano. I suppose he knows what happens in the end. But then we all do, and we would watch I, Keano over and over again.

There's Jerry Springer, The Opera. This is based on a person who is also, but to a lesser extent than Roy Keane, real. It is actually based on Jerry's television programme, a television programme so bizarre that it could not possibly be real.

Jerry Springer, The Opera, was only trotting after the television show in terms of offensiveness. But then conservative Christians are obviously too busy to watch afternoon television, and so the opera came as a horrible shock to them, poor things.

In Ireland, of course, we can only watch and pray for Haughey: The Opera. Which would be so real as to be unbelievable. The language alone would be enough to curl your hair, although the whole thing would undoubtedly turn out to be disturbing.

Reality burst on the entertainment world through the back door of television. But the question is, how did so much reality get on television in the first place? This question has not been asked often enough, even though the answer is obvious and particularly pertinent at the moment.

It was the OJ Simpson trial, stupid.

That's when we sat down, for the first time, to a soap opera which starred real people . . . although we had our doubts about Judge Ito. Who the hell made him up?

Yes, it was the OJ Simpson trial that started all of this. The fact that it was based on the brutal murders of two young people was neither here nor there. The fact that a guilty man walked free at the end of it was neither here nor there either. The OJ Simpson trial gave us all a peek into the privileged private lives of California C-list celebrities. We never looked back.

Now we have the Michael Jackson trial.

The charges against Jackson are quite as dramatic as those brought against OJ Simpson, and Jackson has a lot more to lose. But we television audiences know that that really isn't the point of this television spectacular. Despite the fact that no cameras are permitted in the courtroom we have spotted all the other signs of a celebrity trial. The circus of saddos who parade outside the courtroom . . . Jackson's fans. The shamelessness of the lawyers.

The eerie sight of a celebrity who doesn't realise how profoundly weird he is. The history of abuse allegations which were side-stepped due to the celebrity's wealth and fame. The health scares . . . Jackson taken by ambulance to a hospital suffering from f let's see, flu. Tell that to any working mother. And so on. Once more we're going to be allowed a look behind the green door of fame.

No wonder celebrity trials led to television programmes about ordinary people with their privacy round their ankles. Once you've heard about OJ's obsessive spying on his wife, or about Michael Jackson taking pre-pubescent boys to bed, it's bound to whet your appetite for the goings on in the Big Brother Jacuzzi. No one even asks if Jackson is guilty. Presumably some enterprising Broadway producers are already auditioning very thin young men for the lead part in Michael: The Musical. Now that's going to be a big hit.