Alastair Darling, leader of the Better Together campaign, says further powers would “undoubtedly” be devolved to Scotland if the country votes to no in the Scottish independence referendum.
The former chancellor said he always believed that devolution is “not a concluded business”.
But there must be consensus about the devolution of more powers to Holyrood, the leader of the Better Together campaign said.
Such measures are unlikely to be successful if they are only supported by the governing political party, he said.
He highlighted the Scotland Act of 2012, approved by both Holyrood and Westminster, as setting “a template for how the planned future developments of devolution can be taken forward if Scotland remains in the UK”.
Mr Darling, who was part of the Labour government that established the Scottish Parliament, said: “If we vote to stay in the UK, I’ve always argued that devolution is not a concluded business. Undoubtedly there will be further measures. But the way to do this is through political consensus because I think, in any constitutional change, if one party does it, it is unlikely to stick. You have to try to build a consensus.
“That’s a better way of proceeding rather than for one party to come along and say ‘right this is what we’re doing, you lot have got to accept it’.”
He made the comments during a speech to academics and activists at Glasgow University, setting out the case for Scotland to stay part of the UK.
Voters will decide the country’s future in a referendum next September, with Mr Darling insisting there is a “powerful, principled and positive case for remaining in the UK”.
He said: “It’s a case based on securing our economic future, and sustaining our place in the world. It’s a case based on opportunities for young people and security for the older generation. Above all it’s a case based on staying where we belong, better together as part of the United Kingdom.”