We live in exhilarating times. After years spent in a penitential mush of hand-wringing and name-calling, hardly a day now passes without some public figure unexpectedly poking received liberal opinion in its wobbly gut. Trevor Phillips and the Chief Rabbi both say that multiculturalism has failed. Past migrants speak out against disorganised immigration. Veteran headmasters say exams aren’t everything. Service chiefs announce that rash wars may be lost. The Chief Constable of North Wales wants heroin legalised. This seems to me very healthy: an acceptance that times change.

And now from the retiring president of the National Black Police Association, Keith Jarrett, comes a call to increase the level of stop-and-search investigations of youths – often black youths – who may be carrying knives or guns. He does not say it is a panacea, far from it, but that a lot of black parents “want to stop these killings, these knife crimes, and if it means their sons and daughters are going to be inconvenienced by being stopped by the police, so be it. I’m hoping we go down that road.” He does not expect to be universally popular, but lays aside misgivings about the fact that six times as many black boys and twice as many Asians as whites are stopped this way. The violence, says this black policeman firmly, outweighs these concerns.

Barely had Mr Jarrett’s brave and stroppy speech been reported than liberal opinion rose up sanctimoniously against him. Until now the lazy mantra has been that the police are “institutionally racist”, as the Macpherson report put it, and cannot be trusted. They have to record every instance of searching, and have been threatened with legal action by racial equality watchdogs and accused of poisoning community relations. The riots of 1980, 1981 and 1985 in Bristol, Brixton and Handsworth were triggered by heavy-handed police action against black suspects, mainly in search of drugs or stolen property.

The hated “sus” law empowered police to arrest anybody “loitering with intent” and dated back, quaintly, to the Vagrancy Act of 1824. It was abolished to general approval. And it is true that many a respectable black Briton on his way home from work knows how irritating it is to be stopped for the crypto-crime of “driving while black”. Many a black boy slouching home with nothing more on his mind than homework has been offended by the tactless and ignorant approaches of greenhorn white cops with no manners. As one exasperated teenage musician said, he wouldn’t mind if they would just call him “Sir” like a citizen, rather than “mate, bruv, blood, or son”. A training project in Hackney gets teenagers and police officers to swap roles and see how the other party feels in these fraught little encounters. This is valuable: rough-handed “sus” and searches certainly did trigger 1980s riots.

But this is 2007, and the crimes that police have to prevent are not predominantly drugs or burglary, but murders: often by teenagers, of teenagers. This year alone we have lost scores of young lives to shootings: James Andre Smartt-Ford, 16, in Streatham at an ice-disco; Michael Dosunmu in his bed in Peckham; Billy Cox, Annaka Pinto, Jonathan Matondo, Abukar Mahamud, Nathan Foster, Rhys Jones. Others have lost their lives to the knife: Ben Hitchcock, Rizwan Darbar, Andrew Holland, Martin Dinnegan, Shane Jackson, Samantha Madgin, Sian Simpson . . . it goes on. None of them saw their 19th birthday; some were long years away from it. So many knives, so many guns, so many dead.

And that is how it is in 2007, and why bridling over historic grudges is not useful. In almost all those murders and woundings, the attackers are teenagers, often black. No point denying it. Mr Jarrett is right and brave, a proper copper; and his critics – Nick Clegg and the rest – are copping out. They tend to be mainly white, universally adult and all comfortably off. Whereas those who are telling Mr Jarrett that they don’t mind their sons and daughters being “inconvenienced” are those who live in terrible and personal daily fear that their own well-loved Rizwan or Damilola or Ben will be next.

Another thing that has moved on is the police force itself. It is not perfect, but slowly and surely it is reflecting better the society it serves.

It is harder today than in 1985 (though not impossible) to be an arrogant, racist young cop. After the Macpherson report the Home Office set a target of 7 per cent of ethnic minority recruits by 2009. They are still under 4 per cent, and attrition is worrying; yet the ethnic minority proportion rises faster than overall police numbers. The Metropolitan Police have a particular problem because even though they score 8 per cent, the population in London is now one third from minorities. Police support workers also increasingly represent the diverse community, and this too is useful; it is harder to be an unthinking racist when your workplace is mixed. So – with caution – we can say that the police have changed. Mr Jarrett is aware of this, and if he thinks that the present violence means they need more licence to inconvenience every colour of citizen, give him a hearing.

For if I had teenage sons and daughters now, of any colour from pallid pink to deepest ebony, and if they came home complaining with injured innocence that were stopped and frisked – with reasonable politeness – I would tell them to count themselves lucky. If ten pesterings of innocent teenagers end with one confiscation of a deadly weapon, that’s a result. Of course it should be civil; of course we need “intelligence-led” policing and community reinforcement and all the other good things. But we also need alert, curious, determined police officers on the streets, not afraid to back a hunch.

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