Sign of the crimes: Do magistrates serve the interests of justice and the judged?

It is after one in the morning and an unmarked police car is on routine patrol, purring down Cresset Street. As it reaches the T-junction with Clapham Manor Street, a Metro MG reverses up to it. As the Metro draws level, its occupants brake, take one look across at the plain-clothes officers - one glance is all it takes to clock those haircuts - and grind the car into first gear and away.

The Metro speeds down into Clapham High Street, the police car in pursuit. Somewhere in the warren of streets off the High Street, the police lose them - the young lads at the wheel seem to know their way around.

The police decide it's worth a quick check down the underground car park beneath the estate - a regular dumping ground for joyridden cars. As the officers' car dips down the ramp, three bodies flash across the headlights, hot-foot for the exit. It's them.

The area is soon flooded with officers - it's a 'good shout'. And minutes later, two youths are picked up strolling down Clapham Park Road - a picture of nonchalance, if only they weren't out of breath and sweating.

I walk down Cresset Street nearly every day after shopping on Clapham High Street and collecting my son from the local primary school. The Metro would have screeched past our GP's surgery on Clapham Manor Street and, where the youths were picked up, we regularly push the buggy on a Sunday.

In fact I walk, cycle and drive on these same streets and yet feel I inhabit a completely different world. Never has the science fiction notion of parallel universes seemed so con-cretely realised.

And until a year ago when I started sitting as a JP at the nearby magistrates' court, I knew little or nothing of this other world. I took the kids to the swings, shopped for aubergines and brown bread, nodded to the neighbours and drew the curtains. And all of this unaware that a few hours later a different set of people would take over Clapham's streets and use them to go twocking (taking without owner's consent) and myriad other crimes.

Of course, we all know about the Nineties crime wave, but it isn't until you're in a position to take in the precise details of one of these incidents that the streets starts to change before your eyes. Hearing these stories, you start to perceive an entirely new layer of activity.

Clapham Manor Street, for instance, is a dream: four to five hundred yards of dead straight road, but with parked cars on both sides, it ends up not much wider than a single lane - just right to test your high-speed steering, especially in reverse. And where some park their cars - admittedly firmly locked with anti-theft devices - others dump other people's that weren't quite so well-secured.

Previously, I'd have taken the man pulling a knife and refusing to pay in the Indian restaurant for a racist looking for a fight. Now I know he's as likely to be lonely, with a history of mental instability, who's bolted down the meal only as a preface to this confrontation. He knows he needs and wants in-patient treatment - for the company as much as anything else.

The woman led away by security in the supermarket looked like just another shoplifter to me. Now I know she's feeding a bottomless habit or determined to get herself on probation. With a probation officer behind her, maybe she can get her post-natal depression noticed, or maybe she can get on the list for some half-decent housing.

This kind of small-scale revelation has sometimes left me wondering whether I really am best placed to sit in judgment on this world and its inhabitants. We share the same post code and our feet tread the same pavements, but the

similarities end there.

If you didn't go to school with or grow up across the estate walkway from today's law-breakers, do you really know what makes them tick? And can you really know what sort of punishment or rehabilitation will turn the tide for them?

My colleagues on the bench range from headteachers to entrepreneurs to builders. But I've been struck all the same by a majority consisting of the comfortable, white middle-class, in which I have to include myself.

The Lord Chancellor's department appears to be making efforts to attract a wider spectrum of citizens: political allegiances are carefully balanced, and at my swearing-in, about one-sixth were non-white.

But until London is attracting applications from the conductor of the Clapham omnibus or the greengrocer on Clapham High Street or, let's face it, the unemployed, the justice meted out to the criminals on London streets will never accurately reflect the opinions and beliefs of Londoners.

Certainly, when the problem of graffiti on estates came up at a recent meeting of the Clapham Sector Working Group (an effective forum for citizens and police to combine their efforts), I kept my head well down. As well as the untold grief this vandalism clearly causes, a universal complaint emerged: even when offenders are caught, they are given what are seen to be negligible sentences; of course, on the bench, we would argue that they are far from negligible.

Sentencing in the youth court reflects the Criminal Justice Act and attempts to reform the offender - the court is a last-ditch attempt to avoid criminalisation.

But as we sit there debating constructive and lenient-seeming sentences, we are painfully aware that this policy of attempting to reform the criminal often fails to satisfy the retributive needs of the victim. And we manage this sleight of hand only because we ourselves are rarely or never victims of this kind of crime.

I put myself forward for appointment after a chance meeting with a member of the rural squirearchy who happened to mention that he was also a JP.

'Why is it,' I grumbled to myself, 'always people like him who become JPs?'. The answer was simple: because people like you don't apply.

Jonathan Myerson's latest play 'Angel Standing' will be broadcast on BBC Radio 4 on 8 August.

(Photograph omitted)