It's good to talk, but only on our terms. In an interview today with The Herald, David Cairns, the Scotland Office Minister, makes clear his view that the ongoing debate about Scotland's future should not encompass fiscal arrangements. His intervention is not at all helpful to Wendy Alexander, the beleaguered leader of the Labour Party in Scotland who just happens to be the leading light in the Scottish Constitutional Commission, also encompassing the Unionist Scottish Conservatives and Liberal Democrats.

It's good to talk, but only on our terms. In an interview today with The Herald, David Cairns, the Scotland Office Minister, makes clear his view that the ongoing debate about Scotland's future should not encompass fiscal arrangements. His intervention is not at all helpful to Wendy Alexander, the beleaguered leader of the Labour Party in Scotland who just happens to be the leading light in the Scottish Constitutional Commission, also encompassing the Unionist Scottish Conservatives and Liberal Democrats.

Ms Alexander needs all the friends she can muster. Yesterday she was once more on the defensive, having to try to deny that Gordon Brown, the Prime Minister, wants to downgrade the status of the commission. Now Mr Cairns indicates that Labour and, by implication, Ms Alexander's pet project, should not stray into territory it has no business investigating. Yet Ms Alexander has long been a proponent of fiscal federalism, founded on a mixed system of tax and block-grant funding services.

If this did not entail putting UK and Scottish fiscal arrangements under the spotlight, why is it proposed by Scottish Labour, the Tories and the Liberal Democrats that the commission, advised by finance and economics experts, should examine the assigned share of UK tax revenues model (albeit VAT variation would seem to be exempt)? It would be unfortunate for Ms Alexander, to say the least, if Mr Cairns's contribution were interpreted as pulling the rug from under her feet in the one area in which she sees an opportunity to make badly needed political capital for her party.

The minister's comments are not only potentially damaging for Scottish Labour, they hint of Labour at Westminster failing to appreciate that being seen to dictate the limits of the devolution settlement does not go down well in Scotland, where there is an appetite to debate and explore these boundaries (the SNP would not be in government at Holyrood if that were not the case). It is perplexing that Labour does not heed this lesson, despite the number of Scots from Mr Brown down in government at Westminster (or perhaps because of the number). Fiscal devolution is a debate that will not be stifled; nor should it be. If anything, it has been given a higher profile of late, with Lord Barnett trying, if failing, to establish a committee to review the funding formula that bears his name and is intended directly to affect Scotland's funding. Owen Kelly, the chief executive of Scottish Financial Enterprise, has questioned publicly the SNP's local income tax policy for, in his view, potentially taxing senior business executives out of Scotland. Mr Kelly's contribution could be grist to Mr Cairns's mill. The minister must know, however, that one-sided debates are sterile. There are two sides to the fiscal devolution debate and they must be allowed to flourish. It is the minister's argument that is negative and looks empty.