A couple who had been accused of killing a toddler they hoped to adopt, said "justice has been done" after winning a four-year battle to clear their names.

Ian and Angela Gay, of Hayley Green, Halesowen, were cleared of the manslaughter of three-year-old Christian Blewitt in a retrial at Nottingham Crown Court.

Mr and Mrs Gay, who faced a second trial after the Court of Appeal quashed their original convictions, were accused of giving the boy an overdose of salt.

Christian was just five weeks into a 13-week trial adoption with the couple when he collapsed at their then home in Bromsgrove, Worcestershire, in December 2002.

After four days in intensive care, he died at Birmingham Children’s Hospital, and tests showed an abnormally high level of sodium in his blood.

The prosecution claimed the couple had force-fed him up to six teaspoonfuls of salt as a punishment for being naughty.

But the jury heard expert medical evidence that Christian may have suffered from a rare medical condition which caused his body to retain sodium.

Speaking outside the court, Angela Gay, 40, said: "We have waited for years for this moment and finally justice has been done.

"We would like to thank our family, friends, and legal team. They have been wonderful. They have all supported us so magnificently and we would now appreciate some time alone to gather our thoughts before commenting further."

The jury of eight women and four men took just over seven hours to clear the Gays of one charge of manslaughter and one of cruelty, and there were emotional scenes in court number one as the foreman rose to speak.

Mr and Mrs Gay, who sat holding hands in the dock throughout the six-week trial, hugged each other and wept as the not guilty verdicts were read out.

Members of Mrs Gay’s family, who were present throughout the trial, sobbed in the public gallery.

As they left the courtroom, Mr and Mrs Gay were seen to mouth the words "thank you" to the jury, some of whom were also in tears.

Afterwards, the Gays’ solicitor William Bache spoke of the couple’s ordeal in the years since Christian’s death.

He said: "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."

Mr Bache went on to say that he did not believe that cases of this sort should be brought to trial when so much doubt remained over the science involved.

During the trial, the court heard that Christian, his younger brother Nathan and infant sister Chloe were taken into foster care by Sandwell Social Services when it became clear their teenage mother was unable to cope with looking after them.

After an eight-month vetting procedure, Mrs Gay, who worked as a #200,000-a-year insurance actuary, and her husband were approved to look after the three children for a 13-week trial period.

Mr Gay even gave up his job in engineering to care for the youngsters, but on December 8 2002, Christian fell ill at the couple’s then home in Greyfriars Drive, Bromsgrove.

In police interviews after Christian’s death, Mr Gay, 39, said the three-year-old had been refusing to eat his lunch.

The couple left him alone as they thought he was simply seeking attention, but soon heard a crash and discovered Christian had thrown his lunch on the floor.

Mr Gay told police he thought Christian had been laughing at him, and had put him to bed. Later, the Gays found Christian comatose in the bedroom and took him to Russells Hall Hospital in Dudley. He was floppy and unresponsive, and doctors immediately put him in intensive care.

He was transferred to Birmingham Children’s Hospital, where his condition deteriorated and life support was withdrawn four days later.

The verdict comes more than four years after detectives first arrested Mr and Mrs Gay on suspicion of murdering Christian.

In 2005 a jury at Worcester Crown Court cleared the couple of the toddler’s murder, but found them guilty of his manslaughter.

After 15 months in jail, they were freed by the Court of Appeal, which overturned their convictions and ordered a retrial after 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.

Dr Glyn Walters, a consultant chemical pathologist, told the Court of Appeal there were a number of features in Christian’s case that could not be explained by salt poisoning, but could be explained by the "resetting of the osmostat".

There had only been three recorded cases of the condition in the whole of medical literature, Dr Walters said, and the science was not yet fully understood.

The Crown Prosecution Service released a statement explaining the decision to pursue a prosecution against the Gays.

Reviewing lawyer Charles Hardy said: "In the light of the new medical evidence, we believe we were right to place it before a jury for the second time."

Sandwell Council said the circumstances surrounding Christian’s adoption had already been the subject of a "thorough and exhaustive" review, published in October 2005, which concluded that Christian’s death could not have been foreseen by adoption agencies or social services.

In a statement released after the verdicts by West Mercia Police, Superintendent Steve Cullen said: "This has been one of the most complex inquiries faced by West Mercia Constabulary in recent years and has touched the hearts of everyone involved in it.

"Our thoughts are with Christian’s natural parents and all those who looked after him during his short life."