Speaking after the relaunch of his think-tank ‘Our Scottish Future’, the former prime minister called on Boris Johnson to develop plans for constitutional change and co-operation that would work across the nations and regions of the UK.
The former Labour leader also rejected the suggestion for so-called ‘devo-max’, where the Scottish Government is given full fiscal autonomy, from appearing on the ballot paper.
Mr Brown said the question asked in a future independence referendum would be between change through Scottish independence as put forward by the SNP or further constitutional change within the UK, not the status quo.
Asked whether he wanted to be a figurehead of a pro-union campaign and if he believed a referendum would be held before 2026, Mr Brown said he was “not afraid of a referendum”.
He said: “I’ve got no aspirations to being leader of anything, I just want to get things done.
"I’m not afraid of a referendum. I actually think that we have got all the arguments and will develop all the arguments that will win that referendum.
"I believe if there was a referendum, we would win it, but the truth is that I don’t know what’s going to happen in the next few years’ I’ve been saying ‘get round the table’.
“Everybody has agreed – Nicola Sturgeon, Boris Johnson, everybody – that you can’t have an immediate referendum, in fact you are not going to be able to have it for months or even more than that.”
Pressed on whether he would lead a similar campaign to Better Together in a future referendum given the planned work with Our Scottish Future, Mr Brown said he would not stay silent.
He said: "I am going to speak out for the people who are not being represented at the moment in this debate and I am going to speak out for the needs of middle Scotland.”
The former prime minister’s plans for developing a positive case for the union will include several ‘commissions’ where experts will be asked to present policies to best appeal to ‘middle Scotland’.
Mr Brown said this would be people who felt more Scottish than British, were “patriots” and who wanted to see more co-operation between the UK and Scottish governments.
He said the group would call for a “permanent forum for joint working” between the nations and regions and a “UK-wide constitutional enquiry”.
Mr Brown added: “I say that I don’t think that the future a year or two from now will be independence versus the status quo.
"I think the issue will be in whatever way it is being discussed. It will be change by leaving the UK, the SNP position, versus change within the UK.
"We stand up for change within the UK, which makes it more acceptable to the people of Scotland, change that makes it more in line with people’s desire for co-operation and the desire simultaneously that they have a parliament that works in the best possible way for them.
"I personally think that people are getting very obsessed about courts and mandates and about legal issues.”