France's top rugby clubs have pulled out of plans to form a rival tournament to the Heineken Cup, leaving England's Premiership clubs looking increasingly isolated.
The French and English clubs had planned to play in the Rugby Champions Cup, along with the Welsh regions.
But the French Top 14 teams have voted to stay in the Heineken Cup for at least another year.
Irish, Scottish and Italian sides are already committed to the Heineken Cup.
English and French clubs gave notice 17 months ago to leave rugby union's biggest European club competition and organise a new tournament, with the four Welsh regions signalling their intention to follow in October.
Disagreements about the Heineken Cup's qualification criteria, voting structure, income distribution and future television rights were behind the proposed breakaway.
There is speculation that if the English clubs remain isolated, they will set up a tournament involving South African clubs, or even expand the number of teams in the Premiership.