Superficially, there may be little to connect Shamima Begum, the so-called Isis bride, who wants to bring her baby back to the UK, and Aaron Campbell, the teenager who has been convicted of murdering six-year-old Alesha MacPhail on the Isle of Bute.

Identity of Alesha MacPhail killer revealed as Aaron Campbell

 Begum fled her home in Bethnal Green to join the terrorist group, while Campbell stole a child from her bed and subjected her to unfathomable violence. But together the stories, which dominated last week’s news agenda, demonstrate how difficult we find it, psychologically and practically, to cope with under-18s who commit heinous acts of violence without apparent remorse.

Aaron Campbell and Shamima Begum and have highlighted societys difficulties in dealing with offenders below the age of 18.

How could these apparently ordinary young people have become so desensitised that they could condone or engage in acts of savagery?

We have encountered this disconnect before. When photographs of James Bulger’s killer, Robert Thompson and Jon Venables, both 10, were finally published, most people found it impossible to reconcile their innocent wee faces and the suffering they had inflicted on a two-year-old.

Begum and Campbell are older. Begum was 15 when she ran away, Campbell 16 when he murdered Alesha. Even so, the photographs of Begum larking about on a school trip to Thorpe Park and Campbell bouncing around on a trampoline are at odds with the inhumanity of which we now know them to be capable.

Tributes on the Isle of Bute for Alesha MacPhail, the six-year-old raped and murdered by Campbell.

Their youth makes them a particular source of both public revulsion and fascination; four hundred jihadis have so far returned to the UK from Isis, with one in 10 prosecuted; but only Begum has attracted this degree of attention. The depravity of Campbell’s crime, his lies and the age of his victim made wall-to-wall coverage inevitable, but his age increased its clickbait potential and paved the way for execrable sentences such as these in the Daily Mail: “He is handsome in a metrosexual way” and “Campbell dated one of the most eye-catching girls at his school.”

Under-18s pose a dilemma for the justice system too. As a society we remain confused about the transition to adulthood. Thompson and Venables were clearly children and should have been treated as such. But 15/16-year-olds are more problematic. At 16, you are old enough to marry and join the Army. But not to drink or vote.

A handful of campaigners want to see the age of responsibility raised to 18 in Scotland; others favour a separate justice system for those aged 14-18 and no under-18s in Polmont Young Offenders’ Institution. But even liberals like me struggle with applying such leniency to the likes of Campbell who inflicted 117 injuries on Alesha then concocted a pack of lies to incriminate her young stepmother, Toni McLachlan.

Thanks to the vagaries of the system, a law designed to protect under-18s from the vilification that stands in the way of rehabilitation prevented newspapers from identifying Campbell, but not McLachlan, though she was just two years older and had done nothing wrong.

The killer of Alesha MacPhail, Aaron Campbell, whose anonymity had been protected until Friday.

There is no doubt Begum made a poor impression when she was interviewed by journalist Anthony Loyd in the Syrian refugee camp. She expressed little insight and no remorse for supporting Isis and was scarily blasé about having witnessed decapitated heads in bins.

Her apparent motivation for wanting to return to the UK was not that she had recognised the error of her ways, but that she had lost two babies in the camp and wanted the third to live. Far from being contrite, she seemed to take it for granted the country would take her to its heart.

On the other hand, Begum was vulnerable when she ran away to Syria; as has been pointed out, she was roughly the same age as the girls who were sexually groomed in Rotherham. Loyd, who has interviewed many jihadis, says she displayed enough self-doubt within the constraints of the circumstances to suggest she’d make an ideal candidate for a deradicalisation programme.

Whether or not you see Begum as exploited, she ought to be treated in accordance with international law. The Home Secretary, Sajid Javid, should not have stripped her of her citizenship to further his own political career prospects (especially as there is no evidence she is eligible for Bangladeshi citizenship). Nor should there be any suggestion of separating her from her son so he can be brought to the UK  while she waits for the outcome of an appeal.

Shamima Begum, in a Syrian refugee camp, is shown a copy of the Home Office letter which stripped her of her British citizenship. Picture: ITV News

Campbell’s is a very different case; his guilt has been established and I empathise with those who believe he is beyond redemption. But prisons are supposed to be about the possibility of rehabilitation. The default position is for anonymity for under 18s. This applied to Daniel Stroud, convicted of culpable homicide after stabbing Aberdeen schoolboy Bailey Gwynne to death. Was there really any justification for waiving it for Campbell?

What purpose did identifying the teenager serve apart from satisfying the media which hoped to fill many column inches with pictures? As a journalist, I understand this impulse, but it is axiomatic that the interest of the public is not the same as the public interest.

Naming Campbell allowed salacious reporting, but it also propelled him to centre stage. Those who covered the trial have suggested he seemed to enjoy taking the stand. If this is true, then Alesha’s grandmother has a point: naming him played into his hands.

Given Campbell would have been identified when he reached 18 anyway, perhaps all this is academic. Who really cares if he is targeted in jail? In the days of social media, no-one is ever more than a couple of clicks away from uncovering a name.

Neither Begum or Campbell inspire sympathy. Polls suggest 78 per cent of people think Javid was right to unilaterally revoke Begum’s citizenship A majority of people might also be in favour of executing Campbell. But that doesn’t mean we should bring back the death penalty.

The debate over the way the justice system deals with young people is complex; we don’t, as yet, have a consensus on the age at which offenders should be treated as adults. It’s not an easy question to resolve; it requires careful thought but should probably depend on something more than the gravity of the crime.

A further fear is that politicians and judges are being swayed by public sentiment; that decisions on teenagers such as Begum and Campbell are  being taken less on the basis of cool-headed consideration than in an effort to satisfy commercial imperatives or a bloodlust.

I’d argue it matters a great deal when it comes to Begum. If a Home Secretary can revoke a citizenship without recourse to a court once, he can do it again.

Either way, the rules governing young Isis returnees and/or murderers ought at least to be consistent. And those in decision-making roles should be driven by more worthy considerations than political expediency or the demands of the lynch mob.

Dani Garavelli: Can justice rise above a lynch mob mentality?