A prolific teenage burglar from Borehamwood was sentenced to six months in jail for escaping from St Albans Magistrates Court.

The 17-year-old was sentenced on Friday to a six-month detention training order, after a judge at St Albans Crown Court heard how he used a guard's keys to unlock doors during an escape from the court's cells on November 21 last year.

At the time of the escape, the teenager, who cannot be named for legal reasons, was serving a detention order for earlier offences, and following the escape, in December, he was jailed for 18 months for three burglaries in Borehamwood during the summer.

On the day of the escape, the teenager and another 17-year-old boy from Harrow were being awkward, abusing guards and pressing the buzzer while in custody at the court, prosecutor Harry Bowyer told Judge Findlay Baker QC.

After their cases were heard, the Borehamwood teenager asked a female Securitas guard for a light, and the Harrow teenager asked to use the toilet. After she had unlocked the door and let the Harrow teenager out, the Borehamwood youth put his fingers in the door, before his accomplice grabbed her from behind in a neck-lock and put a sharp object, possibly a plastic knife or the fashioned top of a plastic cup, to her neck.

The Harrow teenager threatened to "slash her throat" if another guard came any closer and demanded the keys, which the victim dropped and the Borehamwoood teenager used to unlock the doors, the court was told.

Kim Halsall, defending the Borehamwood youth, who gave himself up the same day in St Albans, said her client had "no idea what was going to happen until his co-defendant took hold of the lady", and he had bowed to "peer pressure" when told what to do.

Richard Craven, defending the Harrow youth, who was arrested the following day in Harrow, said his client had been threatened with knives by others held at Feltham Young Offenders Institute. He was sentenced to a 12-month detention training order.

Both had pleaded guilty in court to escaping from lawful custody.