A violent teenager who attacked a mother and her toddler and threatened to kill them both has been locked up by senior judges.

Joshua Ingram, 18, from Grimsby, subjected his ex-girlfriend and her two-year-old son to a terrifying ordeal in their own home.

Over about three hours he threatened them with a knife, slammed the child’s head into a wall and threatened to throw him out of a window, and repeatedly told them they would be killed.

The mother believed they were both going to die and used her own body to shield her son from further attack during the incident.

He was spared jail by a judge at Grimsby Crown Court in October last year and instead given a two-year suspended sentence after admitting making threats to kill, common assault and damaging property.

But he was handed detention for three years on Wednesday by judges sitting at the Court of Appeal in London, who said the original term was “unduly lenient”.

Their ruling came after the Solicitor General Robert Buckland QC asked for the sentence to be increased.

Lady Justice Sharp told the court the incident had a lasting and profound effect on the mother, who was forced to move from her home.

The judge, sitting with Mr Justice Garnham and Judge Wendy Joseph QC, also said Ingram had shown “no remorse” and instead continued to protest his innocence and to indulge in “victim blaming” on social media, even after being sentenced.

She added: “In our view, the sentence did not reflect the seriousness of this offending and was unduly lenient.

“This was a serious case of its kind and we consider an immediate custodial sentence was inevitable.

“Both mother and her child were vulnerable and they were effectively held captive in their home, a place where they should have been safe, for a long period, during which time threats to kill both of them were made repeatedly and in venomous terms.”

Speaking after the hearing, Mr Buckland said: “This young man’s violent temper left a defenceless child and mother fearing for their lives.

“The original sentence failed to take proper account of the seriousness of the offence.

“I’m pleased the court has seen fit to impose an immediate custodial sentence and I hope it brings some comfort to the victim.”

Ingram was ordered to hand himself in at Grimsby Police Station by 6pm on Wednesday.