A teenager who made threats to a victim of a robbery after he was arrested has been imprisoned for 18 months.

Gracious Simango, 19, robbed Darren Hartland of a £150 chain - bought for him as a birthday present by his parents - in Watford on October 18.

After Simango, who the victim knew through mutual friends, was arrested the following day he telephoned Mr Hartland's mobile saying if he went to prison Mr Hartland would come to some harm.

Following a two-day trial at St Albans Crown Court last month Simango, of North Western Avenue, Watford, was found guilty of robbery and intimidating a witness.

During the trial Mr Hartland told the jury “Gracious” asked him to drop the charges because he feared he would go to prison.

Gracious promised if he co-operated he would “look after” Mr Hartland, but if he did not “And I go to prison it won't be me you have to worry about, it will be other people”.

Simango had come to the attention of police in the past and received a warning and referral order before committing the robbery.

Simango received a warning in 2003, when he was aged 15, for demanding mobile phones and iPods from a group of fellow school children. One boy handed over a phone before Simango made off on a moped.

In July 2006 he was made the subject of a referral order at the juvenile court for theft from dwelling.

Sentence was adjourned for reports until Thursday when Andrew Kerry asked the court not to imprison Simango immediately.

He said: “There is little I can say in the way of mitigation apart from ask for a suspended sentence. He has said, despite the clear lack of remorse in the report, he would pay compensation if you say to do so.”

In order to suspend any prison sentence the law states it can only be for less than 12 months imprisonment.

Judge Martin Griffith said the offences were too serious to received less than a year's imprisonment.

Jailing Simango for a total of 18 months in a young offenders institution, he said: “You were convicted by a jury, by what I thought was clear evidence, of robbery against someone that knew you.

“That in itself would attract a sentence of 12 months. If it had been on its own I may have been in a position to impose a sentence of less than 12 months and suspend it.

“But to make matters far worse you decided, after you had been arrested, to ring up the victim and try and get him to drop the case because you thought you were going to prison.

“You might not have been going to prison, but now have made the offences so serious that the message has to go out that robbery is entirely unacceptable, and the view that people can be threatened into not giving evidence will not be tolerated by the court.

“This strikes at the very heart of the criminal justice process.”

Simango was found not guilty of another charge of witness intimidation when a black male wearing a hooded top was seen staring into Mr Hartland's home.