A senior Labour politician has called for Scotland to have full control over its finances.
Lord Foulkes claimed the UK Government's proposals to extend devolution in the Scotland Bill do not go far enough.
And he has put forward an amendment to the legislation calling for Scotland to have full fiscal responsibility.
The proposal, known as devo-max, would mean Holyrood ministers would have responsibility for both raising and spending cash.
Lord Foulkes said: "The current Bill does not go far enough in devolving fiscal responsibility to Scotland. I think that the time has now come when we must seriously consider a more radical change in funding devolved governments.
"It is described by some as full fiscal autonomy - I would describe it more appropriately as full fiscal responsibility, so that the responsibility for raising money as well as spending it goes to the Scottish and other governments."
The Scotland Bill put forward by the Tory-Liberal Democrat coalition aims to hand more power to Holyrood in a range of areas including tax-raising and borrowing, air gun legislation and the speed limit.
When the legislation was unveiled last year Scottish Secretary Michael Moore hailed it as the "largest transfer of fiscal power from central government since the creation of the United Kingdom".