A MOTHER was cleared of murdering her four-month-old son yesterday following a retrial ordered after a discredited paediatrician gave evidence at the original hearing.

Margaret Smith, 39, collapsed after a jury found her not guilty of smothering her baby, Keith, at their home in Hull in September 1994.

At the retrial at Newcastle Crown Court - ordered by the Court of Appeal, which found her conviction unsafe - Professor Sir Roy Meadow's discredited theories were not heard, and the jury cleared Mrs Smith, originally from Ayrshire, of murder in less than four hours.

The Newcastle jury was not told during the eight-day hearing that they were involved in a retrial. Nor were they told that Mrs Smith and her second husband, also named Keith, were convicted of killing her first husband, Robert (Jock) Brannan, in 1995. He was found in the bath with 51 stab wounds.

The couple, who blamed each other, were cleared of murder but jailed for six years for manslaughter.

The mother of nine, from a family of travellers, was sentenced to life in jail in October 2002 for her son's murder.

However, she was cleared of killing her five-month-old daughter Kelly, who died in 1992. At the original trial at Leeds Crown Court, Professor Meadow suggested parents who kill a child often take them to hospital in the preceding weeks with a fictitious illness - something he claimed Mrs Smith had done with Keith.

The Court of Appeal quashed the 2002 verdict last April and ordered a retrial into her son's death after Mrs Smith's defence team successfully argued that Professor Meadow's evidence at the original trial was prejudicial and should have been inadmissible.

The Leeds trial came about after Mrs Smith, who moved from Ayrshire to Hull in 1980, was accused by a child witness of smothering Keith.

The girl, aged seven, claimed in 2000 that she saw Mrs Smith put a pillow over the boy's face to stop him crying. In a police interview, Mrs Smith said the girl was "evil" and dishonest.

The jury at the retrial heard there were inconsistencies in the girl's account. Gary Burrell QC, defending, highlighted inconsistencies in the child's evidence and claimed she was a "very good liar".

He also said that, while she insisted she had not gone to school on the day Keith died, a register proved she was present.

Mrs Smith, who suffers from epilepsy and had several fits during the retrial, did not give evidence.

Post-mortem tests showed cot death was the most likely cause of Keith's death, just as had happened two years previously with Kelly.

Yesterday Richard Thompson, Mrs Smith's solicitor, said his client was "pleased and relieved" her ordeal was over.

Mr Thompson said it was unlikely Mrs Smith would claim for compensation.

He said: "I don't think she would have grounds to make a claim. To be successful in a civil action you have to show that in some way the prosecuting authorities did not have a realistic prospect of getting a conviction. Their response to that would be that they prosecuted the case honestly on the basis of evidence they had."

Professor Meadow gave evidence in the trials of Sally Clark, Trupti Patel and Angela Cannings, all wrongly accused of killing their babies and later cleared.