Scottish Secretary Michael Moore told Scottish Liberal Democrats at their annual conference in Inverness that he was consulting on how to have a referendum that was "legal, fair and decisive".
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The Liberal Democrat leader has been attacked after he refused to say that he does not believe gay sex is a sin.
Kerrie brings you Sunday night's forecast
Stronger & colder air gets dragged in from the Arctic by the end of Monday. A bitter wind, overnight frosts and the risk of snow showers