Q:

Why is Labour under pressure over its devolution proposals?

A: Labour wants to give Holyrood control over 15p of the 20p basic rate with an additional power to raise, but not lower, rates in the upper bands. The Conservatives and LibDems want Holyrood to have complete freedom on both, though under the Tory proposal the personal allowance - the threshold at which income becomes taxable - would continue to be set in London.

Q: What's wrong with Labour's plan?

A: Activists Labour for Scotland fear the party is not responding to a public appetite for more radical devolution. The Red Paper Collective believes Labour's limited proposals miss an opportunity for a more progressive tax regime.

Q: Are there other concerns?

A: Economists Paul Hallwood and Ronald MacDonald yesterday warned Labour's plan was the "least desirable" in terms of placing a genuine responsibility on MSPs to use the tax system to boost the economy. They argued that under Labour's proposals, the Scottish Government would not face real pressure to raise money as Westminster would still provide a safety net through the Barnett Formula.

Q: So why is Labour not arguing for greater devolution?

A: Devolving all of income tax would help make the Tories' case for "English votes for English laws" (Evel). If the Tories get their way on English votes, it could prevent a future Labour government relying on its Scots members to establish a working majority.