A group of peers has expressed “astonishment” at the way new powers are being delivered to the Scottish Parliament.
In a highly critical report, the House of Lords constitution committee said the fast-tracked Smith Commission package for Holyrood was “not the way to implement significant constitutional change”.
It questioned the failure to consider the impact of the changes on the rest of the UK, and said both the UK and Scottish parliaments were “excluded from the decision making process”.
The deal was reached by the main party leaders to try to deliver the “vow” on greater devolution made to Scots in the run-up to last year’s independence referendum.
But the peers said the quick time-table did not allow adequate scrutiny or consultation on the package, which includes the devolution of income tax and new welfare powers.
Lord Lang of Monckton, a former Scottish secretary and current chairman of the Lords constitution committee, said: “The recommendations in the Smith Commission report clearly have profound constitutional implications for every part of the UK.
“However the UK Parliament is expected to pass these proposals into law without significant amendment despite having been, in effect, excluded from the decision-making process.
“This is not the way to implement significant constitutional change.
“We were astonished to hear that the government have not properly considered the impact on the rest of the UK of implementing the Smith Commission proposals.
“Piecemeal, ad hoc changes to the Scottish devolution settlement without wider consideration of their impact could well destabilise the Union as a whole in the longer term.
“The major UK-wide political parties need urgently to devise and articulate a vision for the future shape of the Union and its devolution settlements. Without this, there cannot be any long-term constitutional stability.”