EUROPEAN Rugby Cup chairman Jean-Pierre Lux has described the ramifications of a proposed Anglo-French tournament as "detrimental" to the world game.
Premiership Rugby and its French counterparts Ligue Nationale de Rugby, though, served notice last year of their desire to quit the Heineken Cup and Amlin Challenge Cup when the existing tournament agreement expires next summer.
They want changes to the structure of both continental competitions, principally over the number of teams involved, the qualifying process and how funds are distributed.
And disillusioned by what they view as a lack of progress during talks for a fresh competition agreement, they announced plans last week for a new Anglo-French event.
"The ramifications of an Anglo-French breakaway would not only be detrimental to European rugby, but also to the world game," said Lux, writing in Wednesday's Daily Telegraph.
"And it would, in turn, come back to shake the very foundations of the same English clubs who should be entering into genuine negotiations aimed at strengthening European club rugby.
"The issues of qualification, meritocracy and format of the European Cup can be amended by meaningful negotiating, as the history of the tournament testifies.
"The core of this argument centres on the desire of Premiership Rugby, with the support of vocal club owners, to renege on a legitimate and commercially-sound TV contract - which was signed and approved by the board of ERC - in favour of a deal which they chose to progress outside the agreed ERC policy of central marketing.
"This much-trumpeted deal, the detail of which has not even been shared with the Rugby Football Union, is presumably designed to give Premiership Rugby control of the way revenues are shared out. To my mind, this is the sort of control they crave rather than any tournament format change.
"Since the 2005-06 season, ERC's revenue has increased by 106 per cent and is projected to be over E52m (£44m) for 2013-14.
"Can ERC's revenues grow in the future, and is there room for the share-out of the funds to change? Yes, of course. During the last accord negotiations, the shareholdings and revenue splits were altered by general agreement.
"Can the format change? Yes. Can the qualification criteria change? Again, yes.
"But any changes to European club rugby can only be made if decision-makers are prepared to engage and to enter into genuine negotiations to find a solution for the benefit of all, including fans and players alike."