After 18 months the jury is finally in and the verdict is "not guilty" in the criminal trial of Tegan Leach and Sergie Brennan for procuring a home abortion.

Tegan Leach and her boyfriend Sergie Brennan had been charged under Queensland's century-old laws making abortion a crime in the sunshine state. Leach had been charged with procuring her own abortion, Brennan with assisting her. It is the first time a woman has ever been charged in Queensland for this offence. Both faced jail if found guilty.

But as Judge William Everson instructed the jury at 10:00am yesterday it became clear that the prosecution side had kicked an almighty own goal which had just handed the defendants their get out of jail cards.

In the end the whole case boiled down to the expert evidence of Professor Nicholas Fisk, an obstetrics expert from the University of Queensland.

Professor Fisk had been engaged by the prosecution.

His expert opinion on whether or not RU486 was "noxious" would swing the case.

Giving his evidence by remote link from Brisbane on Wednesday, Fisk had agreed during cross-examination that the abortion drugs Tegan Leach had taken had virtually no complications, that they could not be harmful to Leach or cause her to suffer ill side-effects.

As the judge explained to the jury, for the case against Leach and Brennan to be proved beyond reasonable doubt, jurors needed to be convinced that RU486 was noxious to her, not the foetus.

It was a critical point.

If they weren't convinced beyond reasonable doubt, they must acquit the couple. Professor Fisk's evidence had given them plenty of room for doubt.

Professor Fisk had put a brilliant case for the defence.

The defence team sitting up the other end of the bar table couldn't suppress their grins, one lawyer was hiding his smile behind his hands. Defence barrister Kevin McCreanor was spotted yesterday excitedly bouncing up and down on his heels near the court cafeteria. He looked like the cat that had got the cream. The prosecution led by Michael Byrne SC, looked glummer and glummer.

With the acquittal in, both sides of the abortion divide say the verdict sends a strong message to the Queensland Premier Anna Bligh.

But it's not the same message.

"I think this sends a clear message that not even a jury is willing to convict on these charges," Children by Choice's Kate Marsh told reporters outside the Cairns District Court.

"This is not the end, the end will be when they take the entire thing out of the criminal code."

From the other side of this emotional debate Teresa Martin from Cherish Life told reporters, "There's no point in being relieved or sad. We don't see any need for the law to be repealed. Due process has been seen today [Thursday] whether we like it or not."

Keeping abortion in the criminal code she says, "Provides a thin veneer of protection for women who are being pressured into abortion and that would be gone if the pro-abortion lobby got their way."

But if there's a truth about this story it's this: hard heads in the pro-choice camp would have preferred a guilty verdict.

No-one will say it publicly, and certainly none wished Tegan Leach or Sergie Brennan in jail but a pair of martyrs would have been helpful to the decriminalisation cause.

"My heart says acquit and my head says convict," whispered one campaigner as we rode down in the lifts from Court One on level four.

"There's no point dancing around it, these laws can throw women into prison and the public need to see that."

The pro-choice lobby has been agitating unsuccessfully for Premier Bligh to throw abortion out of the criminal code. The Premier has repeatedly said the numbers aren't there. One thing she won't say is that a conscience vote on abortion would expose embarrassing divisions within her own Government. And disunity is the last thing the embattled Premier needs.

In the end it took less than an hour for the jury to return with the not guilty verdicts. The public gallery erupted in cheers and clapping. The jury was sent off with a round of applause, and Sergie Brennan picked up his girlfriend and delightedly twirled her around.

Their 18-month ordeal was finally over.

As the defence emerged from the court into a tropical downpour Ms Leach stopped in front of the media pack and finally spoke: "I want to thank the jury" she said. "It's been hard, you have no idea."

Wendy Carlisle is an investigative reporter with ABC Radio National's Background Briefing program.