Mourners gather at the scene of one of the attacks in Paris

Ireland's top Islamic State terror suspect successfully fought off a deportation order on the grounds that he has an Irish-born son.

The middle-aged man, who first came to this country as a refugee more than a decade ago, is the leader of a small Irish-based network providing logistical support for Isil fighters travelling to Iraq.

The "businessman", who lives in Dublin, was issued with a ministerial deportation order a number of years ago as a result of his connections to Islamic terror groups.

However, the suspect challenged the order, saying that as the father of an Irish-born child, he should be allowed to stay in Ireland.

The father argued he could not be deported, because his son is the holder of an Irish passport and is still in school here.

Security sources revealed that the suspect is the number-one target of the specialist Garda unit, Counter Terrorism International (CTI) which is attached to the Special Detective Unit (SDU).

He is also classified as a major terrorist figure by international counter-terrorism agencies and is kept under constant surveillance.

He has had a long association with extremist Muslim terror groups, including al-Qu'ida.

The Irish Independent has learned that the suspect is a facilitator who provides cash and false documents, including passports, for radicalised young Western men intent on travelling to Syria to fight for Isil.

The terror suspect is the leader of a small group consisting of no more than 13 individuals, most of whom came to this country as political refugees.

They have addresses in counties Dublin, Kildare, Louth and Longford, and meet for prayers at a makeshift mosque outside Dublin.

It is understood that the security services have identified several suspicious cash transfers from this country to accounts in other European banks.

The money is then distributed among Isil fighters travelling to the war zone and terrorist cells operating in Europe.

However, security sources say that the sums involved are relatively small, with the largest amount totalling up to €80,000.

Intelligence sources have revealed that the movements of the group are closely monitored - and that they enjoy "very little if any" support from the Muslim community here.

A security source told the Irish Independent that while the man does not pose a direct terrorist threat to this country, the fighters he helps to recruit for Isil do.

"This individual and his group are facilitating people to travel out there to train and fight in the war where they are radicalised further. The big concern is what happens when they return to Europe," a source said.

"It is a situation where the authorities have to be on constant high alert because, as we saw in Paris, some of those involved were not known."

Gardaí monitor individuals who come here from Britain after being refused permission to travel to countries like Turkey, which are used as a transit point for Isil fighters.

Some of the suspects were detained for passport irregularities, while others were informed that the authorities at their destination had been tipped off about their arrival.

A source said: "These people tend to throw their flight tickets in the bin - and take the boat back to England to try again."

The Garda CTI, which was established last year in response to the growing threat from Islamic terrorism, is a section within the SDU based at Harcourt Square in Dublin.

The unit is under the control of the force's Crime and Security branch at Garda HQ, which has responsibility for national security and is exempt from the control of the new policing authority.

The CTI has its own specialist surveillance unit and officers work closely with international security agencies on both sides of the Atlantic.

It is commanded by Assistant Commissioner John O'Mahoney.

Irish Independent