The man in the woolly hat sounds like David Attenborough. “They go to where the light is. They feel safe there.”

He is describing a species of Homo Sapiens found in Speke, a sprawling urban desert some eight miles from the centre of Liverpool.

Aged 11 to 16, these “moths” can be found in shop doorways or by bus shelters. They claim to be “minding their own business” but Jack Straw thinks otherwise: he believes they are part of “yob culture”. The Home Secretary is proposing nightly curfews in problem areas for children under 16. Legislation is already in place to keep under-11s off the streets - but so far has never been enforced.

The Attenborough sound-a-like is Keith Parle, a youth worker who has little time for Mr Straw.

“More than 40 per cent of people on Speke are under 25. Why does Straw assume that any male teenager is a yob?” His views are echoed by another youth worker, Stuart Walton, from Hamilton, near Glasgow. The curfew plan was piloted in his area. But it proved counterproductive, he says.

“The reduction in crime was minimal and it (the curfew) increased fear and paranoia among adults about their area. The real problem is a perception that kids hanging around the streets are responsible for much of the local crime.”

In fact, they wouldn’t be wrong. Crime in most urban areas is the responsibility of kids. Nationally more than 40 per cent of offenders are under 18 and Speke is no exception. Michael Plunkett, the local vicar, knows the names of a small group of boys responsible for much of the area’s crime. Peter Coventry, a local resident claims just five youngsters cause practically all the trouble.

Mr Coventry, a brave man, also knows the drug dealers - Speke has a big drug problem - and has told them to clear off. He shrugs it off: “So let them shoot me - we don’t want them round here.”

All of which suggests that the Home Secretary might have a point. If the troublemakers are well known and few in number, might it not be a good idea to slap on the curfews?

Mark Soundie, another local, thinks it a silly idea but he accepts that’s a minority view on Speke. “About 70 per cent of the people living here favour curfews. But who will enforce them?” It’s a good question. The major troublemakers come, predictably, from “problem homes”. Their parents, or more likely parent, have little control over them.

If the curfew order is broken is the local authority going to take a poor, single mother to court? And, in the unlikely event that it did, is the magistrate going to impose a fine she would not be able to pay? And, if she didn’t pay, would she be imprisoned and her son put in care? And if the law did take this course, who would meet the cost?

The taxpayer, of course - which is one reason why it is almost impossible to find anyone other than Mr Straw in favour of the scheme. So far, reservations have been expressed by teachers, youth workers, local councillors, civil liberties groups and the plice.

Sceptics would argue that New Labour is not much interested in local councillors and gave up listening to teachers and youth workers many moons ago. But the police are a different matter.

Mr Straw might want to listen to Inspector Ewan Cameron of the Lancashire police. “A curfew is short term. We just move the problem on, but we don’t solve it. Quick-fix measures like curfews may just be like sticking plasters.”

The proposal is that the police can only apply for a curfew order that removes all under-16s from a specific area, regardless of whether they are persistent offenders. This could be after 9pm, or it could be dusk till dawn.

But the reality is that neither police nor councils will seek such orders. The last thing the police want is the problem of enforcing an adults’-only area.

As one Liverpool constable, who asked not to named, put it:“You can’t seriously believe we are going to spend all night patrolling Speke filling the cells with kids. All that would happen is that they would move down the road.”

Alan Smithies, head at Speke community school, is another one who knows who the troublemakers are. “Of course we know them. Police presence around here is negligible. A small group of kids make life hell for some residents. I have one girl whose family are being intimidated by a gang. They will be forced out of the area.

“Superficially you can see the attraction of a curfew. But who is going to enforce it? The major social problems that cause that sort of behaviour can’t be sorted by curfews. It’s much deeper.”

Tellingly the head, youth worker, police inspector, vicar, and the residents all point to another problem: there is nothing for the youngsters to do.

Speke has practically no youth provision. A scheme - hailed a great success - to train youngsters for careers in the sports and leisure industry was axed last year. Michael Plunkett, the vicar, runs a Friday night youth club but even that’s had its grant cut.

Keith Parle, the youth worker with the woolly hat, is downbeat: “For the past few months there has been no provision because of budget cuts.”

The result is that, on a misty January night, Speke is a bleak place. Darren, who claims to be 16 but looks about 12, offers an interview, for a fee. His mates say they will settle for “fags”. They are out of luck but they talk anyway.

As interviews go, it’s not great. Lots of complaints about “nothing to do” and being “picked on”.

Keith Parle and the Rev Plunkett say that all the youngsters want is for adults to take an interest in them. And talking to Darren and his mates one can see what they mean.

From a distance they look a bit menacing - kids out for trouble. Up close they seem ... lonely.

The latest crime figures showing an increase in violent crime - most of it perpetrated by young people - will encourage Mr Straw to press on with his plan.

He has little to lose. If the police choose not to enforce it, then that’s not his fault. And, despite all the drawbacks, it has populist appeal. The curfew policy may not have any practical effect but it will look good in the election manifesto.