A sex attacker who claims he could be killed by red onions in the Irish prison diet if extradited from the UK to serve his sentence in Dublin has been sent packing by top judges.

Peter Ivan Dunne — also known as Ivan Gan — claimed his past experiences of Irish prison food showed that his dietary needs were "routinely ignored", exposing him to a potentially fatal allergic reaction from eating red onions.

Dunne, originally from Coventry, and a convert to Judaism, alleged staff had also sidelined the strict dietary requirements of his faith, denying him onion-free and kosher meals.

His lawyers urged judges at London's High Court to halt his extradition to Ireland on grounds that it would violate his rights to life, and freedom from inhuman or degrading treatment — safeguarded by Articles Two and Three of the European Convention on Human Rights.

However, Mrs Justice Rafferty, sitting with Lord Justice Leveson, threw out his complaints, saying: "The absence of evidence that prison staff in Ireland will guarantee service of exclusively onion-free kosher food does not amount to a real risk of inhuman and degrading treatment."

Dunne now faces extradition to an Irish jail within 17 days.

Mrs Justice Rafferty explained that Dunne, 45, was convicted in his absence at Kilkenny Circuit Court in October 2007 of having sex with a "mentally impaired person". He denied the crime, which dated from July 2001, insisting he had no recollection of the incident.

Dunne fled Ireland during his trial and faces sentence for his crime when he returns there.

Along with the alleged red onion threat to his life, Dunne claimed prison staff had insulted his Judaism, making "religiously offensive jokes" and even ordering him to eat pork.

And he also claimed to have become a target for Republican revenge attacks due to incidents dating back to the 1980's.

But Mrs Justice Rafferty ruled that the High Court "lacked jurisdiction" to hear Dunne's appeal because he had failed to serve notice on the Crown Prosecution Service or the Dublin High Court of his challenge. In any event none of his complaints were "tenable", she concluded.

Dunne, who is currently being held in Wandsworth Prison, also claimed to have experienced dietary problems within the English prison system.