A father who threw his two children off a hotel balcony, killing his son, won permission to launch a High Court challenge today against an inquest verdict of unlawful killing.
Two judges ruled John Hogan's case raised "serious points that are plainly arguable" and gave him permission to seek a judicial review.
Hogan wants to overturn Avon coroner Paul Forrest's ruling earlier this year that his six-year-old son Liam was "unlawfully killed".
Former tiler Hogan, 34, of Bradley Stoke, near Bristol, pushed Liam and his two-year-old sister, Mia, before jumping himself following a row with his then wife, Natasha.
Liam died, but Mia survived the 50ft plunge from the fourth-floor balcony whilst on holiday in Crete two years ago.
The unlawful killing verdict led to a police inquiry that could open up the possibility of a new murder trial in Britain.
Hogan, acting through his sister and with the benefit of legal aid, today asked Lord Justice Dyson and Mr Justice Griffith Williams, sitting at London's High Court, for permission to seek court orders quashing the verdict.
His lawyers argued it was an irrational decision, wrong in law and based on insufficient evidence. The coroner was not represented at the hearing.
Giving permission for a judicial review, Lord Justice Dyson described it as "a tragic case".
He described how the family were holidaying at the Petra Mare Hotel at Ierapetra, Crete, in August 2006, when Liam's death occurred.
The Hogan marriage was unhappy. Before the balcony plunge, an argument had started between the couple and the then Mrs Hogan said she intended to leave her husband and take the children with her.
The judge ruled: "In my judgment it is, to put it at its lowest, arguable that the coroner was wrong to regard Mr Hogan's 'mens rea' (whether or not he actually intended to commit a crime) as irrelevant (to his verdict)."
James Badenoch QC, appearing for Hogan, had argued that the evidence pointed to the conclusion that "Mr Hogan was insane within the meaning of English law" and so did not have the required mens rea, or criminal intent, to kill his son.
Alternatively, he argued the available evidence cast doubt on the issue.
Lord Justice Dyson agreed, saying two Greek psychiatrists had examined Mr Hogan. But it was not entirely clear - "at any rate to the eyes of an English lawyer" - precisely what they were saying about whether or not Mr Hogan understood what he was doing was wrong.
"It seems to me it is not possible for this court to be sure what the outcome of further exploration of the psychiatric evidence would have been, and how it would have impinged on the issue of insanity".
The judge concluded: "In my judgment this application raises serious issues which are plainly arguable and which should be thoroughly aired at a contested - as I assume it will be - judicial review hearing."
Mr Justice Williams agreed that the case raised serious arguments and said permission to seek judicial review should be granted.
Hogan was cleared of murder by a Greek court in January, when a jury decided he had been suffering from "an earthquake of insanity".
He is currently being detained in a secure psychiatric unit in Greece.
In March this year an inquest into Liam's death was told that the Greek trial had ignored evidence from key witnesses. Mr Forrest arrived at his verdict after taking this new evidence into account.
Hogan's older sister, Christine O'Connor, from St George, Bristol, made today's successful application.
His former wife, Natasha Visser, who has married again, was not represented or present at today's hearing, although she is listed as an "interested party" in the case.