Teacher Sion Jenkins was wrongly jailed for the brutal murder of his foster daughter after his wife poisoned their daughters against him, the Court of Appeal heard.

Detectives allegedly used flawed evidence to convince Lois Jenkins her husband was guilty of battering 13-year-old Billie-Jo to death "without a shadow of doubt" early in their investigation.

Clare Montgomery QC, acting for Jenkins, claimed his wife became terrified at the prospect of his returning to the family home in Hastings.

She was accused of gradually coaching their two daughters Annie and Lottie to change the original accounts they gave to police, which provided him with an alibi.

By the time the case came to trial a year later, defence lawyers believed the girls had become hostile to their father.

The decision was taken not to call them to give evidence.

In her opening statement to the appeal hearing in London yesterday, Miss Montgomery said: "With the benefit of hindsight, that decision had disastrous consequences because the jury took the view that Sion Jenkins' account of the afternoon was untrue.

"They may not have come to that conclusion had they known that substantial chunks of his account were supported by his daughters."

Billie-Jo was battered to death with an 18in tent spike in February 1997.

Sion Jenkins, who was headteacher designate at all-boys William Parker School in Parkstone Road, Hastings, was jailed for life the following year.

Miss Montgomery said Lois Jenkins had been faced with "a terrible dilemma for a mother" when she became convinced of her husband's guilt.

She said: "Lois Jenkins was told on February 25, 1997, that Sion Jenkins was undoubtedly guilty, that the bloodstains on his clothing could have no other explanation than that he was the murderer.

"She believed from then that he was guilty. The children now have a mother who believes her husband and father of their children has killed one of their children.

"She is terrified of him turning up. She understands that the children's evidence might lead to her murderous and dangerous husband being released and sent back to the family.

"Any mother faced with that prospect would try to unpick their children's stories. If the children had persisted in saying that their father hadn't done it, a mother's thinking would be to get her murderous husband sent back.

"The children's accounts strongly suggested the murder had been committed by an intruder who had gained access to their home by the back gate.

"Had the jury heard their evidence they may not have convicted Sion Jenkins. It follows that his conviction is unsafe."

Lottie, now 18, has travelled to Britain from her new home in Tasmania to give evidence.

Her sister, 20, has made a statement in a video recording seen by the three judges.

Lois, who divorced Jenkins, 46, soon after his conviction and moved to Australia with new partner Vincent Ives and her four daughters, is to give evidence for the Crown against the appeal.

Miss Montgomery said: "Nobody can be certain where the truth lies in the case but the jury was misled that the blood on Sion Jenkins' clothes came from him murdering Billie-Jo.

"In my submission that certainty was wholly misplaced."

The hearing continues.