Could a rough sense be emerging already of where agreement might be reached in the Smith Commission?

It is starting to feel that way, with several clarion voices identifying demands for near-complete devolution of income tax, as backed by the Liberal Democrats and the Conservatives, and full devolution of income tax, backed by the SNP and Greens, as a workable starting point for discussions, while increasing pressure is piled on Labour to be bolder.

Labour's proposals for Holyrood to raise only 40 per cent of its budget and have control over 15p of the basic 20p rate of income tax are too timid. The latest group to push for a more radical settlement is the Red Paper Collective, which counts among its members several senior Labour figures.

It wants all income tax devolved, to allow for a more progressive tax regime, and proposes a number of other measures designed to reset the balance between corporate and state power in Scotland. The blueprint will do nothing to ease Labour's discomfort, languishing as it is on a bed of nails of its own making.

The party's critics have not held back. The former First Minister Jack McConnell has openly criticised it for being too timid, and now two influential academics, Professor Ronald MacDonald of Glasgow University and Professor Paul Hallwood of the University of Connecticut, have identified Labour's proposals as the least desirable of the UK parties' offerings.

Labour's position is becoming quite simply untenable. It fears the consequences for UK Labour of a bolder devolution settlement but, as this newspaper has pointed out many times, it will be punished by Scottish voters if it is perceived as standing in the way of such a settlement.

In common with an increasing number of parties, academics and other groups, The Herald believes that income tax should be fully devolved and that Holyrood should be responsible for raising most of the money it spends. Like the Red Paper Collective, we feel the Barnett formula should be reformed, to be replaced by a more needs-based system. We do not aim to be prescriptive, but agree with an increasing number of contributors that only this level of devolution can satisfy voter expectations.

Professors Hallwood and MacDonald make a further important point. They stress Holyrood should keep all extra revenues raised in Scotland but that the Westminster block grant should not automatically be increased to bail out the Parliament if it spends outwith its means. This is a crucial principle, since the current devolution settlement allows the Scottish Government to blame Westminster for all budgetary constraints it faces. Greater devolution must mean greater accountability by Holyrood. The academics argue that Labour's proposals do not sit well with this aim, since they are too vague on this point and leave too much fiscal responsibility with Westminster.

The forthcoming devolution settlement must be based on sound principles such as the need for greater Holyrood accountability and giving Scots more control over their destinies. It is becoming increasingly clear which proposals are consistent with those aims and which are not.