English and French rugby clubs pressed on with plans for a breakaway from the Heineken Cup on Sunday with the announcement that their competition would be called the Rugby Champions Cup and open to Celtic and Italian clubs.
Premiership Rugby and Ligue Nationale de Rugby (LNR) said it would be set up in time for the 2014/15 season and be open to teams from all three leagues in Europe.
The Premiership and Top 14 clubs have already confirmed their participation with a joint working group set up, Premiership Rugby said.
The other European league is the Pro12 and involves clubs from Italy, Ireland, Scotland and Wales.
"The competition will be based on the principles of qualification on merit, a strong competition format, equality between the leagues, higher commercial values for the teams and expansion into new European markets," Premiership Rugby said.
The English and French clubs announced on Sept. 10 that they planned to set up their own competition after running out of patience with stalled negotiations over the future of the Heineken Cup.
Europe's two most powerful unions are frustrated by what they see as a qualifying system unfairly weighted in favour of Ireland, Wales and Scotland and want a greater share of income from the tournament.
The Heineken Cup is organised by European Rugby Cup (ERC), who have agreed a four-year deal with pay TV operator BSkyB to screen European club rugby competitions from 2014.
However, rival broadcaster BT has a separate agreement to broadcast the English Premiership and matches involving English clubs competing in Europe.
A statement from the French Rugby Federation later said under International Rugby Board (IRB) rules and the FFR-LNC agreement "no international clubs match or competition can be organised without it nor without its agreement".
"Mediation and talks initiated by the IRB and the ERC are currently under way with all concerned parties," it said.
"That's why the statements released today appear to be inopportune."
The IRB has said it does not want to see an Anglo-French breakaway and does not think it is in the interests of the game.