California’s largest grassroots gay advocacy group has withdrawn its support for the campaign to get gay marriage on the 2010 ballot.

Courage Campaign, based in Los Angeles, said it does not believe the movement currently has enough leadership or financial support to be successful in the next 12 months.

Gay marriage was briefly legal in California but was overturned by the state’s voters in November 2008, who approved a measure called Proposition 8 to ban it.

Chair and founder of Courage Campaign Rick Jacobs suggested that recent defeats, such as in Maine, showed that more time was needed.

He said in a statement: “We must build our ultimate victory from the lessons of our recent disappointments.

“We know that we can change hearts and minds through real conversations with our friends, family, co-workers and neighbours.

“This takes time and has to be built to scale – so we can’t delay. When we go back to the ballot, we must be strong, clear and embracing.”

Equality California warned in August that raising the money needed to fight Proposition 8 next year could be difficult and said that the battle for hearts and minds could be won more solidly in a two-year timeframe, with the aim of getting the issue on the 2012 ballot.

Last year, £80 million was spent on the pro-gay marriage campaign.

This means that those fighting for success in 2010 have lost their biggest sources of support.

Love Honor Cherish, a coalition of a number of smaller groups, is aiming to get one million signatures to get the issue on next year’s ballot.

In other states that allow gay marriage, the right has only been granted through the courts or legislature. It has never been granted by voters.