A large majority of MSPs are likely to back calls by the Scottish government to reject the EU withdrawal bill on Tuesday after Holyrood’s constitution committee said the UK government’s proposals were unacceptable.
David Lidington, the Cabinet Office minister who is effectively deputy prime minister, is expected to make a further appeal for a political solution on Friday when he addresses business leaders at a CBI Scotland lunch in Edinburgh.
MSPs will vote on whether to give the EU withdrawal bill their legislative consent, under a convention agreed in 1998 where an act of parliament at Westminster affecting the Scottish parliament’s powers should get Holyrood’s prior agreement.
That vote is not binding on the UK government but it threatens to force the prime minister into making a highly-controversial political decision to impose Westminster legislation on Scotland against Holyrood’s will.
Unless the two sides reach an agreement before the bill is finally passed by the Commons next month, the dispute will also end up in the UK supreme court at a hearing already set for late July.
It adds significantly to May’s problems with the legislation after she suffered a series of defeats on her Brexit plans in the Lords and is attempting to heal deep rifts inside her cabinet over the UK’s future trading relationship with the EU.
David Mundell, the Scottish secretary, was pressed several times on Thursday to say whether his government would impose the measures on Scotland by Joan McAlpine, convenor of Holyrood’s culture and external affairs committee.
Mundell refused to say because he wanted to wait for the result of next Tuesday’s vote but he indicated that if no agreement was reached, the UK government would implement the consultative mechanism that the Welsh government agreed to last month.
The long-running dispute between the Scottish and UK governments centres on how they will jointly manage 24 areas such as food quality, toxic chemicals and farm subsidies after Brexit, through a series of joint frameworks.
Backed by the Labour group at Holyrood, the Lib Dems and the Scottish Greens, the Scottish government insists that none of these joint frameworks can be changed without Holyrood’s express consent.
The UK government says that gives Holyrood an effective veto over policies operating at UK level and affect the devolved legislatures in Wales and Northern Ireland too equally.
Instead, the UK and Welsh governments have agreed that the devolved legislatures will be consulted on any changes, on the understanding nothing will change without consent. Those measures are also being introduced in Northern Ireland because the UK government is in control at Stormont after its power-sharing executive collapsed last year.
Mundell told the culture committee the dispute with the Scottish government was “a pinhead constitutional argument” since ministers in Edinburgh had already agreed that the 24 areas needed joint agreement at UK level.
Bruce Crawford, convener of Holyrood’s constitution committee, said they were “deeply concerned” that the EU withdrawal bill did not require the UK to get Scottish consent.
“There is scope for a reasonable solution to be found. If there is parity and both governments are treated equally, and both are bound by political agreement, then this can be amicably resolved,” he said.