Nineteen people have already been murdered as part of the two ongoing disputes and detectives fear that the death toll will inevitably grow following the latest marriages of convenience.

The Keane-Collopy gang from St Mary's Park in Limerick has teamed up with a gang from Crumlin led by Brian Rattigan, a 26-year-old who is currently serving a 10 year sentence for drugs possession.

This has led to the McCarthy-Dundon-Ryan gang aligning with a group involved in a bloody dispute with Rattigan. The rival Crumlin gang is allegedly led by 'Fat' Freddie Thompson, a 26-year-old originally from Cork Street in Dublin.

To make matters more complicated for gardai, grafitti appeared on a wall on Windmill Road in Crumlin last week claiming that Liam Keane is having an affair with Brian Rattigan's wife.

Liam Keane rose to public infamy in 2003 when he gave photographers the two fingers after his murder trial collapsed because six witnesses developed collective amnesia.

The 22-year-old has been living in Crumlin on and off for the last six months and has become close to Rattigan's associates. The two groups have been importing cocaine into the country along with state of the art weaponry.

They have agreed to provide each other with logistical support to deal with any "difficulties" they might encounter in the future. This is understood to include hitmen to carry out assassinations outside their usual turf, so it is likely that Limerick gangsters will carry out executions in Dublin in the future and vice versa.

Liam Keane's father Christy is in Portlaoise prison with Brian Rattigan and the two are regarded as particularly close. If Rattigan believes that the accusation is true it is likely that a full-blown war between Rattigan's gang and the KeaneCollopy gang will materialise and the just-formed alliance will come to a swift and bloody end.

Gardai have only recently learned about the extent of the cooperation between the gangs. In April, they foiled a plot by the McCarthy-Dundon-Ryans to import a massive haul of weapons.

Rocket launchers, AK-47s and Uzi-sub machine guns were among the deadly 24 weapon arsenal, some of which was due to be delivered to the Thompson gang.

Even though those weapons were seized, there are plenty more available to the warring factions.

A senior detective said: "There is no doubt that there will be major trouble because formal links now exist between the four gangs. The graffiti will not help tensions but that could have been done by one of Freddie Thompson's men to cause trouble and weaken Rattigan.

Rattigan is no fool and will probably see through this but we are expecting trouble regardless and are doing all we can to prevent it but it will be very tough."