IT was a criminal case that was as traumatic as it was unusual. What started as a well-meaning adoption ended in the death of a three-year-old boy and a couple in prison.

Very few children die from salt poisoning, yet that was the conclusion medical experts came to after examining the body of toddler Christian Blewitt in 2002.

It immediately put the spotlight on Ian and Angela Gay, successful 30-something professionals, who lived in a £500,000 house in Bromsgrove, owned a 30ft river cruiser, expensive cars and had adopted Christian and his younger brother and sister to fulfil their dream of creating the perfect family.

To Sandwell Social Services, the Gays must have seemed the ideal proposition. They were well used to babysitting with seven nephews and nieces, had no money worries and successfully short-term fostered a baby girl, crying when she had to go back.

In September 2002 an adoption panel matched them to the three Blewitt children, whose teenage mother was unable to cope, and the trio moved into the Gays' home at the start of November for a 13-week trial period.

Within a month Christian was dead.

A post-mortem showed he had 11 areas of bruising inside his brain and had suffered a heart attack. He had 30 grams of salt in his blood, a fatally-high level.

The Gays always denied giving Christian salt, but could not explain how it got there.

At Worcester Crown Court in January 2005 they stood in the dock accused of the little boy’s murder.

The jury was told social services had warned the Gays that Christian, who had already suffered malnutrition and neglect, would take 18 months to settle down.

They arranged for the couple to have childcare lessons, but Mrs Gay, then 38, never attended. She blamed the pressures of her £200,000 a year job in corporate insurance.

The family plan had been for her 37-year-old husband, a service engineer, to become a house-husband, while his career-minded wife was to quit work for an initial three months settling in period.

The prosecution alleged that in reality Angela Gay returned to work after 10 days.

Meanwhile at home Christian’s behaviour began deteriorating, in contrast to his two younger siblings who were no trouble. After one particularly difficult evening, he threw his dinner on the floor.

The claim was the Gays saw this as an act of defiance and as punishment the little boy was force-fed four teaspoonfuls of salt and “thumped down” roughly into a cot where he fell into a coma.

Four days later, on December 12, 2002, Christian Blewitt died in hospital.

Ian and Angela Gay always emphatically denied either giving him salt or ill-treating him, but could offer no explanation for the excessive amount of sodium in his blood or the bruising to his brain.

After a seven-week trial the jury found them not guilty of murder, but guilty of manslaughter and Mr Justice Pitchers – who attached no blame to Sandwell Social Services for sending three young children to a previously child-less couple – sentenced each to five years in jail.

For the Gays, their dream of a perfect world with a ready-made family had come crashing down.

However, after 15 months in prison, they were freed on bail when the Court of Appeal overturned the verdict and ordered a retrial upon hearing new medical evidence that suggested Christian may have suffered from a rare condition know as a reset osmostat, which causes the body to retain sodium.

At Nottingham Crown Court in March 2007, Dr Glyn Walters, a consultant chemical pathologist, told the jury this condition would explain the level of sodium in Christian’s body.

The couple hugged each other in the dock as the foreman read out not guilty verdicts. Afterwards Mrs Gay read a short statement, saying: “We have waited for years for this moment and finally justice has been done.”

Their solicitor William Bache added: “They have been through hell for years, including time in prison when both were threatened and abused.

"The worst of it was that Christian died. That is an enormous tragedy.

"Mr and Mrs Gay have lost the opportunity to rear the family they very much wished to have.”