Following a meeting between the Irish, Scottish and Welsh rugby unions on Tuesday, 31 May, the Scarlets, Blues, Dragons and current Celtic League champions the Ospreys, were expelled.
The moves comes following the WRU's proposals for a new Anglo-Welsh Cup.
Welsh rugby's governing body believes that securing a new cup competition between England's 12 premier sides and the Welsh regions would improve the game within the Principality.
"I think everyone is aware of our stance. We've got a duty to ensure our regions survive financially." Explained Welsh Rugby Union chairman David Pickering.
"The Welsh regions need this high-intensity competition, they need regular meaningful games and that's what we will aim to achieve."
However his Irish and Scottish counterparts beg to differ, believing that and Anglo-Welsh cup competition would devalue the Celtic League.
As a result the Irish and Scots have declared that they will set up a new league on their own, excluding Wales and leaving the Celtic League defunct.
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