The 10th anniversary of the referendum and subsequent legislation which created the parliament is a natural trigger to review devolution in the light of Donald Dewar's definition of it as a process rather than an event. With the advent of a minority SNP government whose long-term political aim is independence, while the majority of seats in the parliament are held by Unionist parties, it becomes urgent.

The reality of devolution has kindled a new interest in recalibrating the settlement which goes beyond the political parties, but which has been stifled in the stand-off between the SNP and the pro-Union parties. The national conversation initiated by First Minister Alex Salmond is firmly tied to a referendum on independence or more fiscal powers for Scotland, but does not offer scope for discussion of wider areas of constitutional reform.

The alignment of the three Unionist parties in the Scottish Parliament has reached out to their counterparts at Westminster in recognition that UK politics as well as Scottish politics have been changed by devolution. The majority of the Scottish electorate did not vote for separation in May, but in the year of the 300th anniversary of the Act of Union there is considerable concern about the working of its replacement, characterised most obviously by a new English awareness of the West Lothian Question. At the same time a lack of understanding of the Barnett Formula, combined with measures implemented by the Scottish Parliament which do not apply in England, such as free personal care for the elderly, fuels resentment along with the myth of Scotland being subsidised by English taxpayers.

The financial settlement is the issue which most obviously needs a new road map. In a St Andrew's Day speech last week which set out her personal agenda in advance of yesterday's debate, Wendy Alexander returned to the topic which has particularly exercised her in relation to the powers of the Scottish Parliament: strengthening its financial accountability. In her vision for a constitutional commission, therefore, a key area to come under its scrutiny would be whether moving from a wholly grant-funded settlement to a mixture of assigned and devolved taxes and grant would result in "proper incentives to make the right decisions".

Independence is not the only option for change, but unless all are debated fully it is impossible to gauge the level of support for transferring powers such as the ability to raise a substantial proportion of its revenue or control of energy policy to the Scottish Parliament.

It was the Constitutional Convention which laid the foundations for devolution by canvassing views and debating options. Its power was reduced by the fact that neither the SNP nor the Conservatives took part. This time, the Unionist parties are boycotting the national conversation. A truly independent forum, which goes beyond the political parties in membership but includes them all, just might produce constructive dialogue instead of dissent.