An evangelical group in the Church of Scotland has voiced disappointment after the Scottish Parliament agreed in principle with legalising same-sex marriage.

MSPs voted overwhelmingly in favour - with 98 votes to 15 - at stage one of a new bill that could lead to gay marriage becoming legal in Scotland by 2015.

Forward Together accused the Scottish Parliament of arrogance and said it was not convinced that there would be adequate legal protections for those who cannot in conscience support same-sex marriages.

"In making this decision, the Scottish Parliament has taken to itself the right to redefine marriage, which is a gift from God to human society for the well-being of men and women and for the upbringing of children," the group said.

"The Parliament has in effect said that God is wrong, that his gift is inadequate, and that the divine pattern of gender complementarity, seen to be God's will in both Old and New Testaments, is a mistake."

Forward in Faith questioned the speed at which the Scottish Parliament was pushing ahead with gay marriage.

"The implications of this legislation are of such magnitude that a much longer period of reflection and careful thought was called for," it said.

The group went on to accuse the Scottish Government of ignoring the wishes of the majority of Scots who expressed opposition in the public consultation.

Of the more than 77,000 Scots who responded, nearly two-thirds (64%) said they were opposed to the re-definition of marriage to include same-sex couples.

"In choosing to press on with this legislation, legislation for which the Scottish Government has no electoral mandate, the Scottish Parliament has chosen to ignore the wishes of a majority of those who responded to the public consultation, and has shown that the consultation was nothing more than a waste of time and public money," said Foward in Faith.

"Forward Together believes that most of our elected representatives are now leading the electorate into a wilderness of moral relativity in which not only marriage, as human society has always understood it, is emptied of meaningful content, but so are the very notions of what it is to be male or female. Same sex marriage brings confusion into these elemental distinctions."