A SECOND Scottish independence referendum should not be held until 2039 at the earliest, according to a UK Government minister.

Commons Leader Mark Spencer told MPs a time gap of nearer 25 years is required before the matter should be considered again following the first vote in 2014.

It comes after the Scottish Government published its opening documents in support of independence on Tuesday morning.

The 72-page book was published on the Government's website, as First Minister Nicola Sturgeon spoke at its official launch at Bute House.

Speaking in response to an update to UK parliamentary business, SNP Commons leader Pete Wishart said: “There’s one very significant statement that’s happened here in the UK today and that happened in Bute House Scotland, the First Minister’s office, where we have indicated our intention to get out of this trail of devastation that is the United Kingdom and become a country of our own.

That process has started, that debate is now engaged and by God are we going to win that one.”

READ MORE: Indyref2 to be held with or without Section 30 order, says Sturgeon

But Conservative MP John Baron later said: “In answer to the SNP’s question, we should remind them that they cannot be trusted because when we last had a referendum with regards the union we were assured by the SNP that that would be a once-in-a-lifetime, generational choice.

“They cannot be trusted.”

Spencer replied: “[Baron] makes an interesting observation – once-in-a-generation I think is certainly not five years, I think that would be more nearer to 25 years before it should be considered again.”