Passing sentence in the case of the death of Kamilah Peniston, Mr Justice Holland condemned Britain’s gang-gun culture.

“At the heart of this case is the status of handguns in parts of our society,” the judge said. “A handgun in circulation gives the holder a spurious self-confidence and a perverted self-respect, the status of the armed man.”

The judge, sitting at Manchester Crown Court in October, then passed a sentence many involved in the gun culture debate would view with concern. He jailed Kamilah’s mother, Natasha Peniston, for three years for possessing the firearm that killed her 12-year-old daughter.

According to the judge, there were “exceptional circumstances” that allowed him to hand down a sentence below the five-year minimum term set down in law. Ms Peniston had hidden a gun that had been found by her 16-year-old son and used, accidentally, to shoot dead her daughter. Both she and her son, Kasha, 17, were said to be grief-stricken.

The facts of the case were indeed tragic and unusual, but they were not the exceptional circumstances envisaged by ministers and Parliament when the mandatory five-year term was included in the Criminal Justice Act 2003.

In guidance sent to the judiciary the Home Office said that the five-year sentence, three years for those under18, was intended “to tackle gun crime and gun culture”.

The document added that the exceptions to the law should be “technical offences”. It stated: “Exceptional circumstances might therefore include where the holder of a firearms certificate forgets to renew his authority or where a war trophy is discovered among a deceased person’s effects.”

However harsh it may seem, the exceptions did not include situations like those in Ms Peniston’s case. She, the court was told, had been asked by a boyfriend – described in court as “a serious criminal” – to hide the gun. She had then told her son where it was and the accident occurred when he was playing with the weapon.

Introducing the new sentence in January 2004 Hazel Blears, then a Home Office Minister, said that it would “deter offenders and punish the perpetrators”. Since then, however, ministers have been bemoaning the refusal of the courts to impose the mandatory term. They have been frustrated by defendants’ claims of “exceptional circumstances” and by a Court of Appeal ruling that the five-year minimum did not apply to people aged 18 to 20.

In February last year, at the height of a spate of teenage gun murders, Tony Blair, then the Prime Minister, railed at the lenient treatment of firearms offenders. He called for a minimum five-year jail term for offenders, seemingly unaware that his Government had already enacted such a measure but could not make it work.

Three months later the Home Office circulated a new statutory instrument – the Firearms (Sentencing) (Transitory Provisions) Order 2007 – to all relevant parties.

The wording of the document, written by the Home Office violent crime unit, carried an air of desperation. It read: “This is necessary to give effect to the original policy intention of the Criminal Justice Act 2003: that the mandatory minimum sentence should be applicable to all offenders aged 18 or over.” Yet five months later Mr Justice Holland was still exercising his discretion – passing a three-year sentence on Ms Peniston.

The judge could argue a robust case for not jailing Ms Peniston for the full five years. The death of her daughter because of her action is a punishment that will be with her for the rest of her life. But other judges might have difficulty explaining why serious criminals escaped the five-year term.

This month Kevin Faulkner, 28, was jailed in Manchester for violent disorder, drugs and firearms offences. He received sentences totalling eight years and six months, but the actual jail term imposed for possessing a handgun was only three years and six months. In August last year, at Wood Green Crown Court, North London, Rafael Johnson, 19, was jailed for four years after he pleaded guilty to possessing a firearm and ammunition.

If the five-year sentence is, eventually, to be adhered to universally, many police officers on the front line of the fight against gun crime are sceptical about its deterrent effect. They argue that it is simply not long enough.

One senior detective told The Times: “The people we deal with are not fazed by that – they say, ‘Five years? I can do that standing on my head’. And they can. Because it’s not five years, is it? It’s two and a half at most. Two Christmases, that’s how they measure it. Given that the prisons are full of drugs and they can get hold of illicit mobiles, it’s not difficult. Time passes quickly when you’re stoned.”

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