Opponents of gay marriage in Scotland are being marshalled to vote out politicians who supported the measure, in a coordinated election strategy which could unseat up to ten MSPs
Scotland for Marriage, which includes the Catholic Church, Church of Scotland and Muslim communities, said there are several constituencies where its list of supporters outnumbers the majority of the sitting MSP.
"MSPs need to pay heed to what we are saying and our supporters will not be frightened to demonstrate their feelings at the next election," a spokesperson said.
"For some, their votes could be decisive."
The group's "highly sophisticated database" of 55,000 supporters and marginal constituencies has SNP MSP Bill Kid of Glasgow Anniesland as its chief target.
Kidd will be defending a majority of just seven when his constituents go to the polls next year. Scotland For Marriage said it has 1,178 supporters in his seat.
Iain Gray, former Scottish Labour leader, is ninth on the list, with a majority of just 151 compared to 262 Scotland for Marriage supporters in his constituency.
The group is demanding that MSPs amend the same-sex marriage legislation to include safeguards for freedom of speech, the right to foster or adopt children, access public services and discrimination in the workplace.
The plans cleared their first Holyrood hurdle last month by 98 to 15, in a free vote.
Recent polling showed only 43% of the public are opposed to the move.
A Scottish Labour spokesman said: "Our MSPs voted on the same sex marriage legislation based on what they believed was right.
"While we accept that this issue provokes strong reactions on both sides of the debate, we are confident that most people will recognise these decisions were taken after weighing up the evidence and listening to all of the arguments."