Toulouse president Jean-Rene Bouscatel on Tuesday branded the International Rugby Board's (IRB) decision to start the 2015 World Cup on September 18 as "a declaration of war against (European) clubs".

French and English clubs had wanted a September 4 start to the sport's showcase event, but the southern hemisphere unions preferred a September 25 kick-off to minimise disruption to the Rugby Championship, the tournament that is replacing the Tri-Nations after the inclusion of Argentina.

Bouscatel described the decision to opt for a compromise date in between as a kick in the teeth for European clubs.

"I vehemently oppose the contempt which the International Board has shown concerning the dates for the next World Cup," Bouscatel told AFP.

"It's really a declaration of war against northern hemisphere clubs, notably the English and French," said Bouscatel, the French clubs' representative on the European Rugby Cup (ERC).

"While we asked that it begin earlier in order to have our championship afterwards, they've delayed it by 15 days," he said, adding that there was "no major interest for the southern hemisphere nor the International Board to act in this way".

The IRB has said that the calendar is a compromise between the date September 4, suggested by the RFU, and September 25, preferred by the southern hemisphere.

"This decision is inadmissible, intolerable," said Bouscatel, branding the IRB "the thing" -- a term employed by former French president Charles de Gaulle to describe the United Nations.

"It's the opposite of democracy," he said, adding that the calendars of the northern and southern hemisphere should be more closely harmonised.

"You could perfectly conceive, and it's not iconoclast, to play more in the summer, in order to harmonise things. It would be in the interest of everyone."

The 2015 World Cup is scheduled to run from September 18 to October 31.