Ryanair has lost a High Court action for defamation against three pilots over the contents of an email sent in 2013.

The airline had sued three members of the Ryanair Pilot Group (RPG), Evert Van Zwol, John Goss and Ted Murphy.

Ryanair claimed it was defamed in an email on 12 September 2013 from the RPG headed: "Pilot update, what the markets are saying about Ryanair."

The airline says it falsely implied Ryanair management had misled the market and facilitated insider dealing, among other things.

The 11-member jury began deliberating this morning but this afternoon told the judge they would not be able to reach a unanimous verdict.

The judge then said he could accept a majority verdict on which nine or more must agree.

The jury found the email had wrongly implied that Ryanair had engaged in market manipulation but did not find any malice against the three defendants.

The jury found the email did not imply other wrongdoings as alleged by Ryanair.

Costs were awarded against the airline. It said it was disappointed by the ruling and it intends to appeal.

At the opening of the trial which lasted seven weeks, Ryanair claimed the three men maliciously circulated the email to 2,289 pilots in 2013.

Ryanair also claims it was part of an ongoing effort by the RPG to unionise its pilots and had come following similar false attacks on its safety record.

Senior Counsel for Ryanair Thomas Hogan told the jury the email said Ryanair gave positive indications to investors the previous June, which encouraged a share price increase followed up by a sell-off of shares by airline management.

"That statement was factually incorrect," Mr Hogan said.

He said by publishing that incorrect statement, the defendants were saying, by innuendo or insinuation, that the airline misled investors, knowingly facilitated insider dealing by management, was guilty of market manipulation and conspired with management to abuse the markets.

The three defendants denied defamation and said the words complained of did not mean what Ryanair said.

Their lawyers said words also had the benefit of qualified privilege whereby a statement published to someone with an interest in receiving such information is protected as long as it is not motivated by malice.

In his charge to the jury before it began deliberating, Mr Justice Bernard Barton said the recent news about Ryanair deciding to recognise pilot trade unions for the first time had no bearing on the case.

Mr Justice Barton said members of the jury heard Ryanair CEO Michael O'Leary say the company did not recognise trade unions.

"We all saw Mr O'Leary in the witness box and heard what he said about unions and his attitude to unions," he said.

"Before this case is over, we have all become aware through the national media, that Ryanair has announced it is going to change and maybe that is a source of comfort to the three defendants.

"But is has absolutely nothing to do with this case and must not form any part of this case. Your deliberations concern a pilot update published on September 12th 2013."

In closing arguments for the defendants, Paul O'Higgins said Ryanair's reputation was not damaged by the email update and the "real reason" it took the case was to "shut the beaks of anyone who might open them".

The case was meant to act as a "severe warning" to anyone who might step into the shoes of the defendants.

Mr Goss, the only one of the defendants who was a Ryanair pilot until he was dismissed after 30 years with the airline, had gone "through a life of persecution by Ryanair", counsel said. 

In relation to the sacking of Mr Goss, shortly after he had given an interview to Channel 4, counsel said his client had sacrificed a lot and was not prepared to be dishonest or "be some sort of clapboard holder".

Thomas Hogan for Ryanair said this case was not about how the airline treats its pilots, its negotiating procedures or about safety. It was about a single publication on 12 September 2013.

The defendants had sought to put Ryanair on trial but it was the defendants' actions the jury had to consider, not Ryanair's, he said.

The jury should look at what was their first impression when they saw the email, he said.

While Mr O'Higgins had described the meaning attributed by Ryanair as farcical, ludicrous and fantastically unlikely, it was not so fantastic when one looked at the pre-update communications between the group who drew up the update, including a reference to insider dealing.

The update was, in words used in a communication from one of the RPG group, about "outcasting" and attacking management, counsel said.

Mr Hogan said Mr Van Zwol was central to setting up the Dutch legal entity under which the RPG operated and he was prepared to "push the boundaries" when it came to possible breaches of the disclosure rules which govern the stock market.

Mr Goss had been "painted as a victim", counsel said. However, counsel asked "is he not simply somebody who has a colossal axe to grind" and who has spent most of his career fighting Ryanair?

Mr Murphy, who has 40 years in the trade union movement and was heavily involved in aviation safety, had been described in one letter by Ryanair as "a joke", counsel said.

While this must have been a serious affront to him, it did not put him off and he ultimately got himself involved in the publication of the update.