TONY Blair’s former chief of staff has said it would be “impossible” for the UK to keep Scotland in the Union if a majority wants to leave.

Jonathan Powell, who was involved in negotiations that forged the Good Friday Agreement, also said the UK’s position of not giving into a second referendum will be “difficult to sustain” as the key to the Union is consent.

Powell, who worked for Blair between 1997 and 2007, made the comments in a long-form interview with Basque newspaper Gara, published on Wednesday.

In conversation with journalist Iñaki Soto, Powell was asked for his views on Scotland, Northern Ireland and Catalonia.

READ MORE: Nicola Sturgeon TED Talk: FM promotes Scotland's 'extraordinary' green power

On the topic of Catalonia, Powell said the key for him was “consent” and nodded to the Good Friday Agreement as an example.

He said: “The Republicans accepted that the status of Northern Ireland cannot be changed without the consent of the people of Northern Ireland.

“In return, measures were taken on the sharing of power, the Gaelic, the protection of human rights ... that is, it was not one-sided, but consent had to be given.

“Something similar happens with Scotland. In the long run, it is impossible to think that the UK Government can insist that Scotland stay in if a majority wants to leave.

“In the end, consent establishes that in a democracy a people cannot be governed in the long term against their will.”

The National:

Powell served as Tony Blair's chief of staff for ten years when he was in power

Powell then discussed the issue of whether or not there is a majority in favour of a united Ireland and what measures would be used to decide a majority if there was a vote.

He said: “On the one hand, because the Catholic population is growing and it is likely that soon there will be more Catholics than Protestants.

“For another, Brexit has caused people to no longer support the UK project and support a united Ireland.”

Powell theorised on how this would be decided - consistent polling, the percentage needed for a majority, surveys over six months.

READ MORE: COP26: Nicola Sturgeon asked to ban Iran President Ebrahim Raisi

He said: “The same goes for Scotland. The Tory government is telling the Scots that they cannot have a referendum when a majority says they want that referendum, it is what they have said in an election and the polls mark that majority.

“It is difficult to sustain, because I believe that consent is the key element of politics in the UK.”

We previously told how Downing Street advisors, under Tony Blair’s premiership, privately conceded that Scotland could hold an independence referendum without Westminster’s consent.

An email from the then Prime Minister’s key aide Pat McFadden, ahead of releasing plans for devolution in 1997, also revealed “a couple of very worried Scottish MPs” were concerned about “the slippery slope to independence”.