Leading councillors say there are "real fears" the championship's future in the city is at risk after sponsor 888.com terminated its contract with the World Professional Billiards and Snooker Association.

Gambling website 888.com had signed up to a five-year deal but has pulled out after just three years.

Its sponsorship paid for the staging of the event at The Crucible theatre and prize money.

The WPBSA confirmed the sponsorship had ended - but said the snooker was committed to Sheffield until 2010. A spokesman said: "World Snooker can confirm 888.com has ended its sponsorship of the World Championship.

"World Snooker is working closely with IMG, its sponsorship search partner, for an alternative sponsor to the 2009 World Championship."

It is believed snooker chiefs are trying desperately to find new sponsors amid fears for the long-term future of the event. The Crucible has staged the annual World Snooker Championship since 1977 and is considered by generations of players as "the home" of world snooker.

Sheffield Council says it will be holding WPBSA to its promise to stage the event here until 2010, and said the city would not foot any bills for it.

Labour today urged all councillors to join together to keep the championship in Sheffield and said council bosses should meet with the WPBSA to discuss the future of the sport.

Labour leader Coun Jan Wilson said her party had been long-standing champions of the snooker as it promotes Sheffield as a world-class city, boosts the economy and is cherished by locals.

She said: "Now the new sponsors have pulled out, there are real fears the snooker is once again at risk. The snooker is so well-loved by local people, it really is a part of what makes Sheffield Sheffield.

"Three years ago, when there were fears the snooker was not going to stay in Sheffield, we worked very hard to ensure the World Snooker Championship would continue at The Crucible." Coun Wilson plans to raise the issue at a meeting of the full council on Wednesday and is expected to get cross-party support.