It was an outcome that no-one involved in the case anticipated or sought. The 48-year-old man, who cannot be named for legal reasons, had pleaded not guilty to two counts of unlawful carnal knowledge of a then 16-year-old transition year student at the school in March 2002. The man's wife broke down in tears as judge Frank O'Donnell explained to the jury that sometimes situations arose that made proceeding impossible and such a situation had arisen in this case.

The now 22-year-old woman was so overcome with emotion that she had to be led out of the courtroom as the accused man embraced his weeping wife. For both women, the prospect of giving the same evidence at the retrial under rigorous cross-examination seemed as overwhelming as it was unexpected.

Because of the sensitivity of the case, Vincent Heneghan SC, prosecuting, and defence counsel Feargal Kavanagh SC, agreed the retrial should happen as quickly as possible. It is expected to commence in about four weeks.

Giving evidence, the accused's wife was asked if her husband ever mentioned the complainant by name. "I think he mentioned a girl who was good at English who sometimes sent him texts, " she said.

Detective Sergeant Patrick Marry told the court that mobile phone records showed the complainant had texted the accused 145 times in the 12 months from September 2001. The accused had texted her 85 times over the same period. Although it was possible to decipher when the texts were sent, the technology was not in place to reveal what they said, he added.

Sergeant Marry agreed with Kavanagh that the complainant initiated most of the text messages. The accused also telephoned the complainant five times, while she never contacted him this way.

The accused's wife told the court that she shared a mobile phone with her husband during the year when this communication was going on between the pair and she would answer his calls and have full access to his text messages.

However, she agreed with prosecuting counsel that text messages could be deleted although she said she "wasn't great with mobile phones."

School friends of the young woman told the jury they received gifts from the accused while at the school. One woman said that she felt "disgusted" when he gave her gifts of a rag doll and hair bobbins and a second girl said the accused told her that he "wanted to be friends" when giving her a gift.

The complainant told the court that the man had been her teacher for several subjects. She said he had asked her out to lunch while she was on work experience and kissed her.

She told the jury they first had sex at the school musical when they separated from the main group to look for parts for her broken mobile phone. Later that month, she said she went alone to meet him in his classroom and he told her he was worried about what had happened and did not think it should happen again.

She said they had sex again after that conversation and months later he told her that it would be very serious for him if others knew what had happened and she should not tell anyone.

The woman agreed that she thought she was in love with the teacher and that the sex she claims to have had with him was consensual. She denied being upset that he had not taken up her advances, saying: "He took up my advances in the most serious way possible."

A teacher at the school gave evidence that the accused had his own unique teaching style and was "very generous of his time" with teachers and students.

She agreed that she would not give gifts such as a rag doll to a student but "this individual had his own methods."

In his closing speech to the jury, Heneghan said the complainant gave "very credible evidence" and was "subject to rigorous cross-examination." He said giving presents to students and texting and phoning the complainant was "not a normal teacher-student relationship."

In his closing speech, Kavanagh said it "defies belief" that the accused would take off all his clothes and have sex with the complainant on the classroom floor when other teachers could have walked in at any time. Just because the complainant said the accused had "freckles on his back" wasn't firm evidence that the pair "made love", he added.

He said there was no proof of alleged sexual relations between the pair except the young woman's word: "It's always dangerous to convict without corroboration. Allegations are easy to make but notoriously difficult to disprove."