England warned yesterday that no country will be able to host the 2015 Rugby World Cup unless the organisers can ease the financial risks involved and offer nervous bidders a more affordable deal as the sport attempts to survive the global economic downturn.

Francis Baron, the Rugby Football Union's chief executive, believes the danger lights are already flashing and is urging the International Board to reconsider its insistence that future tournament bids must be secured by a compulsory up-front fee of around £70m.

As ticket sales are the only direct source of revenue available to a host union, Baron says even the wealthiest of nations are unlikely to make a profit. "If England are struggling to make the numbers stack up, who else is going to be able to do it?" asked Baron.

While England remain keen to host the 2015 event they are not assured of government support in the current financial climate, particularly with the 2012 Olympics and a possible 2018 World Cup football bid on the horizon. Bids have to be lodged by next May and Baron believes the IRB should soften its stance when the issue is discussed at the end of next month.

"We would like to bid for 2015 but at present we would have to consider very carefully whether it would be prudent to bid knowing we'd almost certainly incur a substantial loss."

The IRB's price hike is widely seen as an attempt to make up for the anticipated financial shortfall from the 2011 tournament in New Zealand.

The RFU have also revealed that tickets are still available for all the autumn international matches at Twickenham, including the Test against the All Blacks on November 29. Over 30,000 seats are currently still available for the visit of the Pacific Islands tomorrow week.