A blueprint for an alternative to independence has been unveiled by a group hoping to capture the "middle ground" of voters it thinks are likely to vote No in the 2014 referendum but want constitutional change.
Devo Plus aims to persuade political parties to sign up to its "statement of the new union", which outlines how the Scottish Parliament should become more accountable in areas such as taxation.
It suggests a "permanent" form of governance for Scotland as part of the UK after more than a decade of evolving devolution.
However, there is no cross-party consensus on what opposition parties will offer to voters in the event that independence is rejected in two years.
The SNP said the Devo Plus group is well intentioned but argued that only independence will give Scotland power to build on Parliament's achievements.
Former Liberal Democrat MSP Jeremy Purvis launched the Devo Plus paper in Edinburgh and said: "We believe it is necessary that the public can understand what the consequence of the vote will be.
"We believe the case has to be supplied by those that favour independence, and we take them at their word when the SNP say they will publish their proposals for what they mean by independence.
"Equally, the public should have a clear understanding, if they vote No in the referendum, what that means."
His proposal calls for cross-party agreement on the blueprint, which would be reflected in party manifestos.
Devo Plus would give Holyrood and Westminster "accountability" for raising what they spend in Scotland. Taxes transferred to Holyrood would include income tax and corporation tax while Westminster would retain VAT and National Insurance.