It wasn't so long ago that a Panorama documentary on Madeleine's disappearance would have brought the anti-McCann lobby out in force. Instead the Kate and Gerry-baiters were relatively quiet all week, having perhaps found another grieving family to torment in the meantime, or another conspiracy theory with which to fill their time.

Or it could simply be that they're flummoxed by the latest developments in the case. As Panorama reported last week in the run-up to the fifth anniversary of the little girl's disappearance from a holiday complex in Praia da Luz, not only has a year-long Metropolitan Police investigation come down firmly on the theory that Madeleine was abducted by a stranger, it also claims to have good reason to believe she is still alive, even releasing an artist's digital impression of how she might look today, as she approaches her ninth birthday.

This wasn't the narrative which those convinced that the McCanns had something to do with their daughter's disappearance -- the ones who still post videos on YouTube full of cod psychological analyses of the couple's body language to a sinister musical accompaniment, or who leave messages on Twitter peppered with vile, unsubstantiated allegations -- had geared themselves up to expect. For now, no doubt, they remain bunkered in, regrouping, planning the next attack.

It shouldn't take them long. Portuguese police have already refused to reopen the case, dismissing as "mere speculation" claims from Detective Chief Inspector Andy Redwood, who headed up the team of 28 detectives and seven civilian support staff, that their review of 40,000 pieces of evidence had turned up nearly 200 previously unexplored lines of inquiry, meaning that, in all likelihood, the case will remain in suspended animation, files gathering dust, Madeleine forgotten.

That's the atmosphere in which rumours flourish. Already there are mutterings about the stg£2m cost of the review of evidence, and insinuations of political interference, not least allegations that UK Prime Minister David Cameron was only pressurised into authorising a new inquiry by News International, thereby neatly segueing into another of the chattering classes' latest obsessions, that of the Leveson Inquiry. Panorama trawled through that cesspit, too. It shouldn't be too hard for the conspiracy theorists to use it all to come up with a new excuse to reignite the anti-McCann fuse.

Which is incredible, when you think about it. Five years on and the most thorough investigation of the evidence -- involving, in Det Chief Inspector Redwood's words, "turning every single piece of paper over and interpreting and analysing what is contained within them" -- has concluded that all those pulp fiction scenarios involving an unstable mother killing her own child and a controlling father disposing of the body, with both then colluding in an incredibly effective manipulation of an entire police force and the world media, were nothing but the poisonous fantasies which Madeleine's parents always said they were.

Yet the reaction has been so muted that it feels as if this is just another day at the office for the obsessives. Having invested so much time and emotional energy into demonising the McCanns, it's as if they're still reluctant to give up, much less apologise for the hurt that they caused to a family at its most vulnerable.

In a way, that's not so surprising. The campaign to indict the McCanns for the death of their own daughter was fought largely over the internet, where normal decencies rarely apply. Indeed, the plight of the McCanns could almost stand as a metaphor for the rise of social media as the predominant mode of public discourse.

There's a familiarity, even an intimacy, to online conversation which encourages strangers to feel that they have an investment in stories which actually belong to other people. Kate and Gerry were not only the ultimate victims of cyber bullying, but one of its original casualties too, tried and found guilty in the International Court of Twitter, itself only one year old and in its technological infancy when Madeleine went missing. Every gesture, every word, was magnified with an almost Truman Show-style intensity.

In truth, it seems highly unlikely that Madeleine will ever be found alive, regardless of last week's optimistic headlines. Most children abducted by strangers are killed within hours of being taken. There's also the fact that sniffer dogs detected the scent of death in the McCanns' holiday apartment, strongly suggesting that Madeleine may have died that very first night. Sniffer dogs are not 100 per cent reliable; the evidence of their noses only an indicator which needs to be confirmed by other means. But the bathetic title of last week's Panorama -- Madeleine: The Last Hope? -- said it all.

Until that question mark is removed from the story, there will always be room for the malicious to mislead casual observers into continuing to cast suspicion on the McCanns.

The only consolation for Madeleine's parents is that the growth of the internet has been so swift during the lifetime of their ordeal that the cyber bullies now have so many other victims to pick on that they must necessarily have less energy left over to hammer Kate and Gerry.

For those intent on attacking the media, though, there may be other lessons to learn. The then chief constable of Leicestershire Police, Matt Baggott, has already told the Leveson Inquiry into press standards in the UK that he knew at the time when Portuguese police officers were briefing against Kate and Gerry McCann that they were doing so on the basis of a misinterpretation of the DNA evidence, but decided that it was wiser not to put reporters right, even privately.

Baggott acted entirely as the high-minded media monks, shuddering with distaste at any whisper of secret contact between the ladies and gentlemen of the press and the appointed agents of the state, would wish him to act. But the result was that a family was put through hell unnecessarily. It can only be hoped that Leveson does not throw the baby out with the bathwater and end up making it harder than ever for journalists to do their job, just so that an artificial aura of purity can be maintained.