THEY have become a must-have fashion accessory and children as young as seven have them. Often parents give in and buy them mobiles phones in the name of reassurance that it will help keep them safe and they can prove invaluable. But there can also be problems.

Yesterday, it was reported that a 14-year-old boy from Birmingham sent 2,500 text messages in a month. His phone bill ran to 38 pages.

And an investigation by Meridian Television's current affairs series Focus has revealed that children are five times more likely to be robbed for their phones than adults and highlights the problem of bullying by text.

The average age youngsters get their first mobile is now 12 and it is believed that will drop to 11 by next year.

Tonight's Focus programme, which looks into the trend, shows crime reduction officer PC Mark Harper talking to children at Allenbourn Middle School in Wimborne, where half a class of 10- and 11-year-olds owned mobiles.

"I asked them if someone gave them £50 in cash or more, which these mobile phones can cost, would they be waving it around in the street? The answer was no, they wouldn't. But that is essentially what they are doing."

And he said youngsters should keep abusive or inappropriate messages, text or verbal, and report them to the police.

"It can be a criminal offence and we would possibly be looking at an offence of harassment. These people can be caught," he added.

The programme also features youngsters from a Colehill youth centre, where almost all 11 to 13-year-olds have a mobile and some have been bullied by text message.

One said: "It was saying horrible stuff about me and about my mum and it was swearing at me. I would have preferred them to say it to me instead of sending it to me and not knowing who it was from, because it's not very nice."

Another said: "Nobody knew my number and I didn't have the faintest idea who it was from. None of my friends would do that to me. I got really scared."

Youth worker Tim Oliver said: "I see mobile phones as value-free. I don't see them as evil or totally good. Unfortunately some people have chosen to use them in negative ways, but they can be used in positive ways too."

He can text young people who seem to be having problems letting them know they can call if they need to chat without putting pressure on them and also sends messages to wish them luck in exams and remind them of forthcoming events.

And for many parents the advantages still outweigh any fears. They know they can contact their children when they are not with them and in turn the children can call home if they are in any trouble or have simply missed the bus home.

The secret is teaching youngsters to use their mobiles responsibly, said PC Harper.

Police are hoping to visit all schools in the eastern division to give advice and postcode phones. They are currently arranging a trial at Queen Elizabeth School in Wimborne.

When mobiles are found or handed in there is often no way of identifying the owners, but officers are looking to offer the phone marking facility at enquiry offices and also recommend making a note of the serial number, obtainable by typing *#06# into the phone.

Thefts are on the increase in this area but so is mobile phone ownership.

And although there has been a great deal of publicity about phones being snatched from people's hands on the street, PC Harper said we shouldn't be overly concerned as the problem is far worse in other areas than here.

He said people are far more likely to lose their phone or have it stolen when they put it down somewhere unguarded.

But he warned that thieves might be watching to see what you do with your mobile once you have finished using it.

"That doesn't mean don't use it when appropriate, but tuck it away when you don't have to," he said.

The Meridian Focus investigation will be shown on Meridian at 11.30pm tonight (May 17).