Questions are asked if her actions led to the torture of innocent people

Adar Drycin (Storm Birds) claims that Gladys Aylward - who was immortalised by Ingrid Bergman in a Hollywood film - became a spy for China.

It says that this led to many of her colleagues being tortured, including Cardiff-born David Davies, who was one of her closest friends and allies.

Mr Davies's son, Murray, said his father suffered appalling treatment as a result.

"He was captured and thrown into this 2,000-year-old prison in Taiwan, and sentenced to five years," he said.

"He had horrific treatment and was tortured and kept awake at night."

Aylward, who went to bible college in Swansea, was a devout Christian and came to believe that God was calling on her to spread his word in China.

She was played by Ms Bergman in The Inn of the Sixth Happiness, and was portrayed as a heroine who led almost 100 Chinese children on a long and dangerous journey to escape the invading Japanese force.

Gladys Aylward was played by Ingrid Bergman in a Hollywood film

But the programme questions whether her actions led to the torture and imprisonment of innocent people by the Japanese, including Christian missionary David Davies.

The pair met in 1935 and became great friends and colleagues.

Wanted woman

Soon after, it is claimed that the Japanese discovered that Aylward was a spy and made her a wanted woman.

Realising that the lives of the children in a home she ran for orphans may be in danger, both her and Mr Davies planned the infamous escape where Aylward led them to the safety of the Shensi province.

But Mr Davies, having stayed behind, was captured and accused of being a spy.

His son said the Japanese tried to make his father admit that he was a spy - but he refused.

"They got two of his converts, who were thrown into prison as well, and they chopped one's head off in front of him," he said.

"Another one - they crucified him. This chap went through crucifixion rather than denounce my father."

David Davies finally returned to his roots and spent his last years in Swansea.

"He never held it against Gladys Aylward at all," said Murray Davies.

Adar Drycin will be broadcast on Tuesday at 2100 GMT on S4C.