Phone safety tips

Avoid using your phone in the street Keep your phone out of sight Use PIN codes to lock your phone Turn off the ringer Don't walk and txt Record the phone's unique IMEI number

The clampdown had been urged by ministers, following a sharp increase in the number of mobile phone thefts.

A Home Office study published earlier this month suggests thefts of mobile phones in England and Wales have surged, with more than 700,000 snatched last year.

It estimates the overall number of stolen mobiles is more than double the 330,000 figure officially recorded by police.

Schoolchildren - often targeted by other youths - are at least five times more likely to be targeted by mobile phone thieves than adults, with 48% of victims aged under 18.

Users are advised to keep phones out of sight

Lord Woolf said that except in very exceptional circumstances a custodial sentence would be the only option available to the courts.

The tough sentences would apply "irrespective of the age of the offender and irrespective of whether the offender has previous convictions", he said.

The lowest appropriate sentence was 18 months, but terms of up to three years would be imposed for offences involving no weapons.

Where weapons and violence were involved, offenders would be sentenced to up to five years or more.

'Unduly lenient'

The judge called on mobile phone manufacturers and service suppliers to increase their efforts in "reducing the attractiveness" of phones to thieves.

The government has also said that with a mobile phone stolen every three minutes, the industry could be doing more to reverse the figures.

Lord Woolf, sitting at the Court of Appeal in London with Mr Justice Aikens and Mr Justice Pitchford, allowed a plea by the Attorney General that the sentences given to two 19-year-old robbers in separate cases was "unduly lenient".

One of them, Adrian Lobban, of Regency Close, Collyhurst, Greater Manchester, had been joined by two accomplices to rob two 16-year-olds of a mobile phone at knifepoint in Greater Manchester.

Phone theft statistics

Mobile phone stolen every three minutes in UK Average age of thief is 16 Up to half of phone theft victims are under 18 Source: Home Office

Lobban had initially received a six-month detention sentence, which the Appeal Court judges increased to three-and-a-half years.

In the other case, Christopher Sawyers, of Sheldon Walk, Smethwick, Warley, West Midlands, had pleaded guilty to three robberies.

He had originally received a sentence of community rehabilitation and punishment orders, but was on Tuesday ordered to serve two-and-a-half years in detention.

In a third case, the judges allowed an appeal by 17-year-old Stephen Quanne, of Bradford.

They cut his four-year sentence to three years, but only because of his youth and the fact he had used no violence when he robbed a 14-year-old paper boy of his �80 phone.

'Serious social problem'

Lord Woolf said such robberies, in which the victims were mainly vulnerable young or elderly people, were undermining the criminal justice system.

The only way the message is going to get home ultimately is a few sentences of exceptional severity

Julian Young, solicitor

Statistics showed that 70% of adults in the UK used mobiles, and ownership among younger people was even higher, he said.

Julian Young, a solicitor who has himself been a victim of mobile phone robbery, told BBC News tough measures were needed to stem the rise of the crime.

"I don't think you can lay down absolute guidelines, but obviously this is a very serious social problem and the only way the message is going to get home ultimately is a few sentences of exceptional severity," he said.

"If the courts make it quite plain to all those who are tempted to get involved in offences of this sort - an offence that is relatively easy to commit - then hopefully the number of offences committed will fall."

The government wants to see initiatives from mobile phone companies, and with them and police are studying the feasibility of piloting text-bombing of stolen handsets, successfully used in The Netherlands.