Young people are to be offered mobile phone 'top-ups' in return for information on robberies, as officers step up the fight against street crime.

Officers hope the incentive will encourage schoolchildren to turn in offending classmates following a sharp rise in the number of juvenile-on-juvenile muggings.

Youngsters will be able to report information about muggings anonymously and will be rewarded with pay-as-you-go credits for their mobile phones.

The Max Your Air campaign follows the launch on Monday of a countywide crackdown on crime by West Yorkshire Police's Target Initiative.

The Home Office-funded crackdown began with a seven-day blitz in Bradford and Keighley, in which 60 officers are taking to the streets to deter would-be offenders, responding quickly to incidents and picking up suspects.

It coincides with the launch of the Telegraph & Argus's own Safer Streets campaign aimed at freeing our city from bag-snatchers, mobile phone thieves and robbers preying on the vulnerable.

Detective Superintendent Mark Milsom, who is heading the robbery initiative, said: "Many robberies are committed by young people on young people, often people they know or go to school with.

"But schoolchildren may be afraid to pass on information, whether they are victims themselves or just know who is carrying out the robberies.

"Children who steal from other children are bullies. By letting us know who they are, they are helping their friends as well as themselves.

"If children know who is carrying out these crimes, they should contact us in complete confidence."

l Pupils at Nab Wood School in Cottingley were today treated to a performance by the acrobatic boyband 4orce, followed by an anti-drugs presentation as the robbery scheme gets under way. All 11 to 16-year-old West Yorkshire pupils can also access the force's website and pick up robbery prevention advice, as well as and enter a free draw to win FM mini radios and other prizes.

Operation Target co-ordinator, Chief Superintendent Adam Briggs, said: "This gives potentially vulnerable victims a chance to fight back against those committing robbery.

"The Max Your Air scheme means they can ring Crimestoppers anonymously. Useful information will be rewarded with top-up points for their pay-as-you-go mobile telephone. Nobody, apart from the phone's owner, need know."

To visit the Max Your Air pages on the West Yorkshire police web-site go to www.westyorkshire.police.uk