A judge has issued a warning to youngsters that the courts will not tolerate street robberies.

Recorder Sandra Keen sent out the message as she locked up a 16-year-old boy for three years and nine months for his part in a series of attacks last September.

During one incident at Keighley rail station a teenager had something sharp pressed into the back of his neck and was told to had over everything he had got.

Bradford Crown Court heard that cash was taken from the boy's wallet before his three attackers ran off.

Yesterday Mohammed Ifzal Zafar, of Jasmin Terrace, Girlington, Bradford, was sent to a young offenders institution after he admitted taking part in that robbery and being involved in three similar offences.

Two days after the first attack, Zafar robbed a 14-year-old boy of cash and within a fortnight he had also taken part in a robbery incident involving a motorist.

The final offence related to an attempted robbery involving a 15-year-old boy, who was confronted by Zafar and two other youths in Lister Park.

Barrister Timothy Capstick said it was clear the offences were committed when his client was with older people.

''This defendant is someone who is easily led,'' he said.

He pointed out that Zafar had had the good sense to plead guilty to all matters and he stressed that he was still only 16.

Recorder Keen told the teenager he had pleaded guilty to particularly unpleasant offences and young people had to realise the courts view such matters seriously.

''I am sure you are aware how seriously the courts take this sorts of matter and it is always a great shame and a great tragedy when somebody of your age appears before a court for offences of this nature,'' she added.

But she said she was able to give Zafar credit for his guilty pleas and pointed out that if he had been older the sentence would have been longer.

''I have to send out a message to people who are tempted to be led on by other people, and I accept that is probably the case in your case, that the courts will not tolerate this sort of offence.''