A schoolboy who wore a prosthetic disguise and hair pieces to carry out armed robberies has been sent to prison.

Miles Alura, 16, disguised himself as an elderly man to steal £50,000 of jewellery from a shop in Kent in July, and wore false dreadlocks during a robbery at a jewellers in Mayfair, London the month before, when he escaped with £100,000 of stock.

On both occasions he and a different accomplice threatened staff before tying them up and making their getaway.

Yesterday Alura, of Camden Road, London, who was identified after reporting restrictions were lifted, was jailed at Kingston Crown Court for five years after admitting conspiracy to rob, two-and-a-half for possession of an imitation firearm and five years for robbery, to run concurrently.

Another 16-year-old boy, from Stoke Newington, London, was sentenced to three years in prison for robbery and conspiracy to rob, while a 15-year-old from Holloway, London was given a 12-month detention and training order for conspiracy to rob and possession of an imitation firearm.

Neither of Alura's accomplices, who also admitted the charges, can be named for legal reasons.

The court heard that on July 3 Alura and the 15-year-old went to a jewellers in Longfield, Kent.

Alura, who was wearing facial prosthetics, make-up and a hair piece to disguise himself as an elderly man, produced two handguns and threatened staff.

Terrified workers and a dog were tied up using handcuffs and a dog lead, and the pair stole £50,000 of jewellery.

A member of the public called the police and Alura was arrested in a nearby garden, where officers also found the two guns and parts of his disguise.

A bag containing the jewellery was found near the shop.

The 15-year-old boy was arrested after he ran to fields three miles away, during which time he got rid of most of his outer clothing.

Detectives from the Metropolitan Police's Flying Squad linked this robbery to another committed at a jewellers in Mayfair on June 7, by Alura and a 16-year-old boy.

The pair entered the shop on the pretext of discussing custom jewellery, but instead jumped over the counter and threatened staff, pretending they had a gun.

Workers were tied up and the pair escaped with £100,000 of jewellery. This time Alura wore false waist-length dreadlocks.

Police found fingerprints belonging to them both on paperwork - including school history homework and a drawing of the plan of the store - which was left at the scene.

Detectives found that Alura and the 16-year-old boy had been to Kent to scope out the shop and plan the robbery.

DC Vicky Bailey, from the Flying Squad, said: "These were violent armed robberies during which innocent members of staff were terrorised and genuinely feared for their lives.

"It is even more shocking to know that this level of violence was inflicted by three school boys who went to extraordinary lengths to research, plan and get away with these offences, demonstrated by Alura's sophisticated disguise.

"These young men now face considerable terms of imprisonment where they will have plenty of time to think about the consequences of their actions."

Det Con Angela Costin, from Kent Police, said: "These are horrific crimes and have caused significant distress for the victims, not only in the short term but probably for the rest of their lives.

"The very fact that the offenders are only of school age is harrowing and it is concerning to think that they have committed such heinous crimes with such conviction.