The Scottish government has postponed a decision on whether to legislate to make it the first part of the UK to allow same-sex marriage.

If legislation is introduced members of the Scottish parliament are expected to vote through the measure. This will put pressure on MPs in Westminster to support the prime minister in his attempts to do the same for England and Wales, despite strong opposition within his own party and from the Church of England.

The cabinet has, however, rejected a referendum. "Cabinet views this as an issue of conscience not constitution," said an official.

The Equality Network, the lesbian gay and transexual charity that campaigns for equal marriage in Scotland, said it was "hugely disappointing that yet again we are being told to wait for an answer that never seems to come".