Brown backs new powers for Holyrood

But he said that process could also see some powers switch back from Holyrood to Westminster, and gave as examples some aspects of terrorism legislation and control over future foot-and-mouth outbreaks.

During a BBC Scotland interview for The Politics Show, he also mounted a strong public defence of Scottish Labour leader Wendy Alexander.

Mr Brown gave her his public backing both in her leadership role and in her plans for a fresh study of the devolved settlement.

Some Labour MPs are thought to be particularly unhappy at this, arguing that to open up a new debate about the powers of the Scottish Parliament can only help the SNP.

But Mr Brown defended the plan for what Ms Alexander has described as a commission, although he calls it a "review", and will point out that the move has been taken on board by a vote in the Scottish Parliament.

Asked of the possibility of more tax powers emerging from this review, Mr Brown will say: "Well this is what any review should look at. Nobody should pre-judge it."

However, he said a decade on from devolution experience had shown that some powers may need to return to Westminster, specifically when tackling UK wide issues.

He said: "If you take for example terrorism it's clear when you look round the United Kingdom that if you have a terrorist incident there is no Scotland only, Wales only or England only approach to that.

"Terrorism can effect the whole of, if you like, the islands and indeed the whole of the United Kingdom and there is a case for looking at whether in security and terrorism we have got the right balance."