HOW and why a 15-year-old boy was released from a Hampshire psychiatric hospital only to be killed when he stepped in front of a high speed train hours later, will be laid bare today.

An inquest was due to open this morning into the death of schoolboy George Werb which is expected to hear how doctors allowed him to go home just hours after being given an anti-depressant tablet – despite having suffered a previous adverse reaction to the drug.

Hours later his body was found on tracks close to his home, having been hit by a train travelling at 75 miles per hour.

Lawyers acting for George’s grieving parents Joanne and Justin, claim the teenager had been allowed to leave The Priory Hospital Southampton, which is based in Marchwood, without a proper risk assessment.

Today’s hearing comes as a Serious Case Review has been commissioned into the 15-year-old's death and treatment at the Hythe Road hospital.

And it follows a report by heath watchdog, the Care Quality Commission, published in November last year which was critical of some aspects of care for young people staying at the hospital’s specialist 10-bed Kingfisher Ward.

Representing the family, Mark Bowman, partner at law firm Fieldfisher, told how before being admitted to The Priory last year, George had been concerned over the medication Fluoxetine he was being prescribed.

In particular, he held delusional beliefs that the medication he was given was having adverse side effects, Mr Bowman said.

The inquest is expected to hear how on May 24 last year, the day after being admitted to The Priory, George was placed on one-to-one observations.

Over the course of the following weeks they were reduced and his medication regime increased and on June 27 George was given Fluoxetine for the first time at The Priory.

Lawyers claim that within a couple of hours of being given the drug, and without a risk assessment being conducted as to whether or not George might react to the drug, he was allowed to go home.

In the early hours of the next day, George left the family house near Axminister in Devon before walking to the local railway line where he was hit by a fast moving train.

In advance of the inquest, Mr and Mrs Werb issued a joint statement It said: “Losing George is an unimaginable loss to our family, our pain is beyond expression. “To lose our son who had so much more to accomplish and live for is totally heart-breaking”.

Mr Bowman said: “This is a deeply tragic case and I welcome, on behalf of George's family, the opportunity to question those responsible for his care and treatment in the lead up to his death.”