A mob on the turn is an ugly sight. It is a beast of savage power and small brain. Those the mob supports are carried shoulder high but, should it turn, they will be as quickly torn to pieces. The media is the mob today and the couple whose fate teeters in the balance are Kate and Gerry McCann. Since May, and the disappearance of their daughter Madeleine, they have been held aloft. They have received sympathy, support and adulation. They've been shown to us as beautiful, devout and heartbroken parents; the blameless victims of an evil world. Their one fault was to trust their children would be safe while they slipped out to eat.

Then the Portuguese police cast the terrible shadow of suspicion on them, making them suspects in Madeleine's death. Before they left Portugal, people on the streets of Praia da Luz had started to hiss. Here, the hissing is beginning to seep out from the British media as it starts to hedge its bets. It's a sound as depressing as it is dangerous.

One reporter, who had only praise for the McCanns last month or even last week, now writes of long- harboured doubts and suspicions. Another said he always wondered why a paedophile would risk taking a child from an apartment with a well-used alley at the back of it and a main road at the front. Yet another remembered how Kate fell silent when asked why she hadn't used a baby-sitter and how she walked away when asked why she left the apartment doors and windows unlocked. This reporter also said Gerry could appear arrogant.

Another newspaper queried why, on the night of the disappearance, the two-year-old twins didn't waken when Madeleine was lifted from between them. It asked why they continued to sleep through their mother's hysteria when she found Madeleine gone. Why did they carry on sleeping when the apartment filled with people? The implication is obvious: they were sedated.

Can you feel the chill wind of condemnation? Can you imagine what will happen to this family if hostility takes hold? The media is a many-headed hydra. No one newspaper or television station will rip the couple to pieces but there are many journalists camped outside the McCanns' home, each with a separate master; each in competition with the others. Meanwhile, the executives who issue instructions to stake out the McCanns are not on the ground to see the overwhelming effect of the media army.

Well, let me state a few points for the defence. Would a paedophile take a child from an apartment which is overlooked? You bet he would. I'll give you two of many examples. On a hot summer night in 1995, nine-year-old Sophie Hook was sleeping with two cousins in a tent in the garden of a house in north Wales. She was abducted, abused, battered and thrown into the sea. In December 2005, a man walked through the back door of a house in North Shields. He took a six-year-old girl from her bath, assaulted her in a car and dumped her, naked, in a nearby street. An active paedophile is, by definition, a high-stakes risk taker.

Why would Kate McCann fall silent when asked an accusatory question? Does it mean she has something to hide? Of course it doesn't. I wonder how often she had been asked the question. I wonder how she's managing to appear in front of the media at all. When had she last slept or eaten? Did she know the answer anyway? If one of my children had been taken shortly before their fourth birthday, I would be in such a state of shock, grief and guilt that I wouldn't be able to cope with any such question. I would be much more likely to have a ready explanation for leaving the doors unlocked if I had done it to cover some foul deed of my own.

If I were Gerry McCann, would I be arrogant? This is a young father trying to compensate for failing in his primary role of family protector. Maybe he needed to feel in control of the search for his daughter. He is also a hospital consultant. It's a profession that is no stranger to arrogance: but it isn't a crime.

The suggestion that the twins were sedated is more pertinent since Kate is apparently suspected of accidentally killing Madeleine by overdosing her with sedative. She and her husband strenuously deny this. I have heard of no medical evidence that the children were doped but even if it exists, it doesn't necessarily implicate the parents. If a kidnapper watched the family and planned the abduction, would they have risked Madeleine creating a fuss and the twins setting up a racket? Isn't it at least possible that he or she used something to keep the children quiet?

We're told dogs detected the scent of a corpse on Kate's clothes. She is a GP who saw five dead people the week she came on holiday. It is said that DNA from a speck of blood in the boot of a car the family hired 25 days after Madeleine disappeared, matched DNA in their holiday apartment. The McCanns have retained the car to have their own tests done. There is, however, a general acceptance that Kate could not have transported a corpse that had been hidden for almost a month in high temperatures. Such proposals are beyond nightmare.

From what we know of the police evidence, it is about as convincing as Tony Blair's dodgy dossier on the Iraq War and deserves as little credence. What is not disputed is that on the night the child disappeared, Portuguese police were slow to respond. How can anyone judge the McCanns' behaviour in those early days when they were confronted by the knowledge that borders were not closed, searches were not carried out and all the time the clock was ticking and Madeleine was possibly being taken to her death or worse.

Somehow her parents remained dignified. Now, months later, they realise the Portuguese police are focusing their efforts on prosecuting them, instead of tracing and finding their child. If the McCanns are innocent, I don't know how they are clinging to sanity.

Before the media turns on them, fearing they've been too uncritical to date, let me sound a warning note. Let every journalist remember Sally Clark. She was portrayed as a heavy-drinking career woman who killed her babies rather than let them interfere with her lifestyle. Then she was exonerated. Unjust imprisonment destroyed that young woman even before her premature death.

Yesterday we saw pictures of two-year-old Sean and Amelie McCann. If they are extremely fortunate, they will grow up with parents and an elder sister who survived a traumatic summer. If they are not, they could have their parents imprisoned for the unlawful killing of a sister who is never found. If you'd had the sort of luck that Kate and Gerry have had of late, what would you be expecting? Meanwhile, as posters of Madeleine bleach in the sun, despair must be snapping at their heels.

I believe in the presumption of innocence. British journalists were right to support these young parents and I hope they continue to do so. I, for one, will not be joining any growing hiss of the mob.