TWO teenagers suffered violent robberies at the hands of armed thieves out to steal mobile phones.

A 15-year-old boy was threatened at knifepoint and searched by two males.

The men one wearing a black hooded top with a scarf covering his mouth, the other in a black bomber jacket struck in Wolsey Road, Moor Park, at 5.30pm on Friday, January 25.

One was white, about 17 years old and 5ft 9ins tall.

His black accomplice was of similar height and stocky build. He had short, black hair.

In the second, unrelated, case, an 18-year-old was stopped at about 8pm the previous Sunday, in the subway under Rickmansworth Road.

A man demanded his phone and pulled out a knife. The victim was told to hand over his gold neck chain. The mobile was snatched and the robber ran off.

He was a clean-shaven black man wearing a dark beanie hat with a blue stripe, and dark denim jeans.

There has been a 75 per cent rise in reported robberies in Watford between April and December 2000, compared with the previous year.

Much of this is attributed to gangs intent of stealing mobile phones.

Children are at five times greater risk of having their phones stolen than adults.

A police operation to tackle phone robbery and street crime has been running in Watford for three weeks.

High visibility patrols have been conducted in the town centre and Cassiobury Park, two hot spots.

The areas are targeted on days and at times when mobile phone owners are being hit.

Specialist dog handling officers and traffic police have been working in support of the operation.

Detective Chief Inspector Graham Weston said: "Early indications suggest that we have already stemmed the worrying rise in this type of crime in this area."

In January, a 16-year-old from Middlesex was arrested and charged with phone theft in Watford High Street.

He is due before magistrates next month.

The most senior judge in England, Lord Chief Justice Woolf, said this week mobile phone muggers should be sent to prison for up to five years.

He said jail sentences would apply, "irrespective of the age of the offender and irrespective of whether the offender has previous convictions".

Under the Hertfordshire initiative, mobile phones can be taken to police stations and given an identity mark.

This will help trace stolen phones and aid in bringing prosecutions.

Schools are also being visited by police and pupils with phones, are encouraged to have them marked.

About 150 phones have been marked so far.

Anyone with information on the robberies, or crime in the town should call 01923 472900.