IS SOMEONE who films an incident on their mobile phone a ghoul or a citizen witness? Maybe they can be both at the same time, their ghoulish first instinct turning later into a potential source of information for the police.

This question arises today following the incident at Leytonstone tube station in London on Saturday night, in which two men were reportedly attacked by a knife-wielding man who is said to have declared: “This is for Syria.”

The alleged attacker has been named as Muhaydin Mire, 27, from Leytonstone. He has been charged with attempted murder after a 56-year-old man received injuries described as “serious”, and another person was injured too.

Those people who filmed the incident on their phones earn a telling off from today’s Daily Mail, which condemns them for being “ghouls”.  In the same breath, the Metropolitan Police is asking for people to hand over any such footage to help with their investigation.

Here we have a modern paradox. The desire to film or photograph anything and everything is perhaps morally unhealthy – and useful at the same time.

My theory is that human beings haven’t changed, it’s just that modern life has equipped them differently. In the past people would have stood by and watched as an incident unfolded, with one or two attempting to intervene in some way.

Now the ratio of watchers and doers is about the same. But because the watchers all have mobile phones, they can film or photograph what is happening.

Is this a new human instinct or an old one changed by technology? People have always been inquisitive, nosey or ghoulish: what’s changed is that they are now equipped to exercise those qualities in a new way.

If mobiles had been around in the days of public hangings, people would have been there with their phones, recording the death from the first drop to the last spittle wriggle at the end of the rope.

A generation is now growing up that feels the need to record everything it sees: almost as if their own eyes aren’t reliable enough – and perhaps they aren’t, as police often say that witnesses all report having seen different things.

A more workaday aspect of this is that as the police deal with ever-mounting cuts, they will have to ask more often for help from these citizen witnesses/ghouls.

News today is often refracted through social media, in good ways and bad. The bad side is the passing on of information that is unreliable or plain wrong. And the good side is the way a few words can be turned into a moral slogan.

During the incident at that London tube station, a witness is said to have shouted at the alleged attacker: “You ain’t no Muslim Bruv.” His words soon began trending on Twitter, becoming an anthem for the moment: five words that seem to say an awful lot.

SYRIA FOOTNOTE: I was driving round yesterday with the radio on. A Syrian woman exiled in London appeared on the World This Weekend on BBC Radio Four. She made an impassioned, clear and intelligent case for saying that Britain and the West were wrong in their approach to her country.

Her main point was that Assad’s regime had killed seven times as many people in Syria as Isis had – and that our bombing efforts now would only strengthen Assad. She also claimed that Assad had in a sense created Isis as a useful distraction to deflect attention from his regime.

In short: our intervention could only make things worse in her country. I wonder if David Cameron was listening. Not that he ever does – listen, that is.