Plans for a post-Brexit internal market must not be imposed without consensus and agreement between the devolved nations and the UK Government, MSPs have warned.

The Westminster Government wants to establish a new internal market between the four nations at the end of the Brexit transition period, but the Scottish Government has claimed “every devolved power could be undermined” by the proposals.

Holyrood’s Finance and Constitution Committee has been hearing evidence on the plans and has now written to the UK’s Business Secretary urging “mutual trust and respect for the existing constitutional arrangements”.

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Responding to the Government’s white paper consultation, committee convener Bruce Crawford criticised the lack of detail about a new trade framework and claimed there was “little scope for meaningful engagement”.

Business Secretary Alok Sharma declined to give evidence to the committee about the plans, but a UK Government spokeswoman previously said the proposed internal market “will ensure the free flow of goods and services across every part of the UK, while upholding the devolution settlement”.

Arguing EU-controlled powers will be transferred to the devolved administration, she added: “This will give the devolved administrations power over more issues than they have ever had before, without removing any of their current powers.”

On behalf of the committee, Mr Crawford said new structures must not be imposed without devolved governments’ agreement because “trade-offs and balances are involved in making an internal market”.

He said: “There is an onus on all four governments and legislatures across the UK to work constructively together to seek a solution to this complex and challenging issue.

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“This must be achieved through mutual trust and respect for the existing constitutional arrangements within the UK.

“In particular – as this committee has emphasised on numerous occasions – the UK Government, post-Brexit, must respect the devolution settlement.

“There must be a transparent and inclusive public debate on the white paper proposals which allows all interested parties and the wider public to contribute.

“The significance of the proposals for all citizens across the UK means that the solution cannot be left to the UK Government to decide.

“A consensus needs to be achieved and this requires a much longer, inclusive and more detailed debate than what is currently being proposed.”

Giving evidence about the proposals on Wednesday, Scotland’s Constitution Secretary Mike Russell accused Prime Minister Boris Johnson of “running a clear and deliberate anti-devolution policy”.

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Mr Russell argued the proposed legislation considers Westminster to be sovereign in trade and regulation disputes, and the UK Government “have a veto on everything”.

Warning the Scottish Government is considering legal action to challenge the plans, he said: “This is an outrageous power grab and it is a major weakening of devolution, and it should not be permitted to take place.

“My view is that it reveals completely the agenda of the current UK Government, which is hostile to devolution and hostile particularly to Wales and Scotland for exercising their rights under devolution.”