THE mother of a tragic teenager who became the youngest person in Britain to die in custody has launched a legal challenge to force a fresh inquest into his death.

Adam Rickwood was just 14 when he hanged himself in the privately-run Hassockfield Secure Training Centre, near Consett, County Durham in August 2004, just hours after being restrained using controversial methods.

Yesterday, his mother Carol Pounder started proceedings at the High Court in London to have a second hearing into his death opened, after branding the original jury inquest a whitewash.

That month-long hearing, held at Chester-le-Street Magistrates' Court in May 2007, absolved staff of blame in the death and ruled that he had intended to take his own life.

The jury made no criticism of Adam's treatment and said there were no system failures in the centre's regime.

The teenager, from Burnley, was found hanged by his shoelaces from a curtain rail in his room.

Six hours earlier he had been restrained and carried to the room by four officers, one of whom had used a painful "nose distraction technique" to stop him struggling.

Weeks before his death he had written to his mother saying he would kill himself if he was not taken out of the centre.

Yesterday Richard Hermer, appearing for Mrs Pounder, asked High Court judge Mr Justice Blake to order a fresh inquest, saying: "The subject matter of this case could not be more serious."

He said Adam was "a deeply vulnerable and troubled child" whose early adolescence was marked by drug abuse, educational difficulties and a history of self-harm and suicide attempts.

Mr Hermer argued that the centre staff had no power under the relevant rules to restrain Adam as they did and argued that the failure of Durham Coroner Andrew Tweddle to inform the jury of the illegality of the restraint measures used meant the inquest was fatally flawed.

He also argued that Mrs Pounder was entitled under Article Two of the European Convention on Human Rights to a "thorough and exhaustive" investigation via a fresh inquest.

The hearing is expected to continue today.