A TEENAGE robber held a knife to another teen's throat and stole his mobile but the phone's GPS led police straight to his door.

Craig Greener of no fixed abode was jailed for robbery at Worcester Crown Court following the incident in Redditch after he was tracked via the phone he stole.

The court heard how 18-year-old Greener, who was 17 at the time of the offence, robbed 18-year-old Callum Galbraith on Sunday, February 21 last year at just after 1am.

Mr Galbraith was walking home when he noticed two males standing against a lamppost, thinking little of it at the time. He continued on his way through a cul-de-sac which led to Harport Road and through an underpass, taking out his iPhone, unaware at this stage he was being followed.

Darron Whitehead, prosecuting, said: "He realised there were footsteps coming up quickly behind him. He saw two males behind him, one at quite a distance but the defendant was running quickly towards him."

Greener grabbed Mr Galbraith's right wrist and pulled his phone from his hand as the complaint tried to grab it back.

Mr Whitehead said: "The defendant said: 'I'm going to stab you!' He had his hand in his back pocket and produced a pen knife, three to four inches in length."

Mr Galbraith continued to attempt to recover his phone, holding onto the defendant's jacket.

"This prompted the defendant to point the knife towards Callum Galbraith's throat" said Mr Whitehead.

The robbery lasted around 60 seconds with the victim described as being shaken but uninjured.

Mr Galbraith returned home and a GPS application on the phone allowed police to trace it to Birchfield Road in Redditch, the defendant's father's address.

Officers attended that address at around 4am the same day and Greener was found with a second man in his bedroom, his description matching that given by Mr Galbraith.

His iPhone was also found wrapped in silver foil and knives were recovered. Greener was picked out at an identity parade.

He admitted robbery at the first available opportunity before magistrates.

He has three previous convictions for battery and convictions for possession of a knife and burglary.

Jason Aris, defending, said his client, who appeared at court via video-link, was already a serving prisoner after being convicted of six offences.

He asked the judge to impose a concurrent rather than a consecutive prison sentence for the robbery, arguing that the existing jail term had had a 'salutary effect upon him'.

Mr Aris referred to his client's youth and described the robbery as 'an opportunistic offence'.

His honour Judge Robert Juckes QC said the defendant had had the good sense to admit the robbery at the earliest available opportunity.

He said: "You're young but you have accumulated a significant record and, if you continue to accumulate a record of this sort, particularly if associated with violence, the sentences are going to get longer and longer.

"It would be unfortunate to spend the rest of your life locked up.

"This was a particularly serious robbery. It occurred at night. It involved a chase and the threat with a knife.

"It was not just producing the knife but putting the knife to the neck of the attacked person.

"It's fortunate there was no injury."

The judge imposed a two year prison sentence which will run concurrently to the one he is already serving.