Dissident republican groups in Northern Ireland are rapidly growing with currently more than 600 members, with the Real IRA posing the biggest threat according to senior security, intelligence and dissident sources.

The latest security analysis suggests that member numbers of the different break away dissident groups has now reached over 600. Estimates prior to this had suggested membership at between 300 and 400.

Sources confirmed to the Irish Times that the former leader of the Real IRA, Liam Campbell has stepped down. Campbell is thought to have played a key role in the Omagh bombing in August 1998 where 29 people were killed including a mother and her unborn twins. A new younger member with a strong Derry focus has taken over leadership as the prior leader was supposedly ousted from the helm.

Campbell who is currently in Maghaberry Prison, near Lisburn was moved for his own safety out of the republican wing last week. Police intelligence recommended his removal from the wing after they feared he was under imminent death threats from fellow prisoners who were also members of the Real IRA. The former Real IRA leader is remanded on custody in Lisburn before he faces extradition to Lithuania on arms smuggling charges.

“Our assessment is that Campbell is gone and that a new leadership is in place which is determined to build up a more dangerous and more cohesive structure,” the source told the Irish Times.

Sources confirming Campbell's removal from the paramilitary body said it illustrated the groups plans to strengthen its organization and structure.

“There is disinformation out there that the Real IRA is a fragmented organization run by little autonomous groupings but that is not the case, it is united and well organized,” said a well-placed dissident source.

Other Republican dissident groups active in Northern Ireland include Óglaigh na hÉireann  which was a splinter group from the Real IRA and the Continuity IRA.