McGrath went on to challenge the game's institutions, by which he meant the national unions under the umbrella of the International Rugby Board, to flex their regulatory muscles by preventing the English clubs and their fellow rebels in France from setting up a new cross-border competition.
He also questioned the motives of the Premiership teams, accusing them of turning their backs on the tournament not because of issues over qualification and competitive structure, but because they want to frustrate the Heineken Cup's recently extended broadcasting contract with Sky Sports to see it fall as a consequence of the European Rugby Cup (ERC) being wound down. "That is clearly not something the board of ERC is prepared to accept," he added.
The Sky deal is at the heart of this hugely damaging argument. A little over a year ago, the Premiership clubs signed a 152 million ($297 million) broadcasting contract with BT Sport, awarding exclusive rights to domestic top-flight rugby and insisting any future European games involving English teams would also be screened by the newcomer. News of the rival agreements was made public within hours of each other and neither side has given ground since.
McGrath insists he was properly mandated to conclude the Sky agreement; the English faction disagrees.
Meanwhile, the potential fall-out for rugby in Wales was illustrated by the former international lock Derwyn Jones, who now acts for Sam Warburton, the Cardiff Blues flanker and national captain who led the Lions in Australia during the summer. "Sam has told the Blues he wants to stay in Wales next season," Jones said, "but the region isn't able to offer him a contract at the moment because of the mess that exists in Europe."
Aware that the other three regional sides in the principality - the Swansea-based Ospreys, the Llanelli-based Scarlets and Newport Gwent Dragons - have already lost leading players to big money on offer in England and France and will be at serious risk of losing a lot more if there is no European tournament next season, the Welsh Rugby Union chief executive, Roger Lewis, offered his services as an honest broker.
"We're all in danger of losing the plot here and we have to focus on the principal point, which is that this is the greatest club rugby competition in the world and we must get the right people around the table at the right time to discuss the right things," he said, adding that his union was willing to negotiate on new tournament structures and a fresh distribution of income.
"There's 19 years of history and legacy here and starting all over again is unnecessary."
Which was helpful, until he added: "Our position is unequivocal: we have to honour our position with Sky."
As the English clubs are every bit as unequivocal in their position on the broadcasting front, there is no fertile ground for compromise.
- Independent