Gardaí are planning to use a private jet to repatriate Gerry Hutch to face a murder charge in relation to the Regency Hotel shooting in 2016.
Mr Hutch is expected to be extradited as soon as Thursday after his final appeal against extradition to Ireland was rejected by a Spanish Appeals Court. He is being held in a Madrid prison.
Sources said plans may be delayed, depending on the security situation. The current plan is to charter a private plane to bring Mr Hutch to Dublin directly from Madrid, under Garda escort.
Extraditions are typically carried out on scheduled, commercial aircraft but gardaí believe this may pose a security risk in Mr Hutch's case. Consideration has also been given to using an Air Corps plane and flying Mr Hutch to Casement Aerodrome.
Non-commercial aircraft have been used in the past to extradite serious criminals. Last year a private plane was used to extradite John Slattery to the US to face charges of illegally trafficking endangered black rhino horns.
Jonathan Keogh was extradited to Ireland from the UK on an Air Corps aircraft in 2017 for the charge of murdering Gareth Hutch, Gerry Hutch's nephew. Mr Keogh was convicted last year and given a life sentence.
A military aircraft was also used to repatriate John Gilligan in 2000 for the charge of murdering journalist Veronica Guerin. He was acquitted of murder but jailed for drug dealing.
Mr Hutch is expected to be brought to Ireland amid an extensive security operation, including an armed escort to Special Criminal Court 1 at the Criminal Courts of Justice, which is sitting on Thursday morning.
There he will to face a charge of murder relating to the 2016 attack, which led to a bloody escalation in the Hutch-Kinahan feud.
It is understood a number of gardaí have already been dispatched to Spain to organised his transportation to Ireland and are currently preparing a security assessment.
Once in Ireland, Mr Hutch is likely to be remanded in custody to Cloverhill Prison, unless he is granted bail on appeal to the High Court. Murder carries a mandatory life sentence in Ireland.
In fighting his extradition in Spain, Mr Hutch argued he was under threat in Ireland from criminal groups. The Spanish court rejected this argument, stating the Irish authorities are capable of keeping him safe.
However the court did concede to a request by Mr Hutch to be transferred back to Spain to serve any sentence which might be imposed by the Special Criminal Court.
It took into account that the Dublin man is a Spanish resident who has paid tax there since 2012 and whose family live in the country.
Any transfer of Mr Hutch to a Spanish prison if convicted would likely be welcomed by the Irish Prison Service due to the significant threats he is likely to face in an Irish prison as a result of the feud.
However it is not clear if Irish authorities could consent to such a transfer. The Irish Transfer of Prisoners Act 1995 allows prisoners to serve their sentences in other countries under certain conditions, as long as they are a national of that country.
It is understood Mr Hutch is resident of Spain but not a citizen.
Mr Hutch (59) has been in custody since being arrested on the Costa del Sol last month by the Guardia Civil. A search for him began in April after Ireland issued a European Arrest Warrant in relation to the Regency attack, which occurred on February 5th, 2016, during a weigh-in for a boxing event.
Daniel Kinahan, the Dublin criminal named in court as a leading figure in the Kinahan cartel, was at the event and gardaí believe he was the gunmen's main target. However, he managed to escape as several other men were shot, including David Byrne (34) from Crumlin, who died from his injuries.