Brown entered the fray over the region's future today with a speech in Scotland saying Brexit makes the case for Scottish independence weaker, not stronger.
He said Scotland should be able to set some tax rates, sign international treaties, and have more control over agriculture, fisheries, environmental regulation, employment and energy.
Brown played an important role in 2014 when he helped convinced Scottish voters to stay in the UK.
Scotland First Minister Nicola Sturgeon seeks another independence referendum, but Prime Minister Theresa May has rejected holding another vote now.
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