The future of the Heineken Cup is looking increasingly uncertain, with the French clubs joining England's in refusing to sign a new accord to replace the one which runs out at the end of the season unless certain demands are met.

A European Rugby Cup board meeting scheduled for tomorrow has been postponed until next month. The English clubs have stalled on a new deal because of the Rugby Football Union's refusal to grant them greater voting and share rights in ERC. France's Top 14 clubs are threatening to boycott Europe in protest at next season's fixture list which they say will require them to play league matches in midweek to avoid clashes with internationals and be without leading players for half the season, threatening to reduce the value of the domestic television contract which is currently being negotiated.

Not playing in Europe would free up a number of weekends. The president of League National Rugby, Serge Blanco, arrives in England tomorrow to speak to club officials in a bid to enlist their support ahead of next month's ERC meeting. The RFU has continued to take a hard line with clubs, saying it will not agree to a change in the way the Heineken Cup is organised until they negotiate a new agreement over the management of elite players.

The French federation faces another problem after the Six Nations committee threatened to move matches away from Stade de France next year in a row over perimeter advertising. The organisation which runs the ground, Consortium Stade de France, sold advertising which should have been reserved for the tournament's sponsors, the Royal Bank of Scotland. France have two home matches in the Six Nations, Wales in February and Scotland in March, with ticket sales for the latter suspended this week pending a resolution.