UK ministers have been accused of refusing to respect devolution after Scottish and Welsh leaders warned proposed freeports are being pushed through without their consent.

The row has intensified after Welsh First Minister Mark Drakeford told a House of Lords committee on Wednesday that “in the current UK Government, we face for the first time in the history of devolution a government that is instinctively hostile to devolution”.

His comments came after Boris Johnson reportedly told Tory MPs that devolution in Scotland had been a “disaster” – remarks seized upon by the SNP. The party also pushed back at the UK Government’s Internal Market Act, which it claimed was a post-Brexit "power grab" of devolved responsibilities.

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As part of post-Brexit measures, the UK Government is proposing to set up freeports at strategic sites across the UK. Goods that arrive into the freeports from overseas will be exempt from tax charges.

Eight locations in England have been chosen and it is thought two could be selected in Scotland.

But the Scottish Government has instead drawn up its own proposals for green ports which would adapt the UK plans and offer incentives to businesses that adopt fair work practices and contribute to Scotland’s transition to a net zero emissions economy.

Both the SNP Government and the Labour Welsh Government have not agreed to the plans being progressed – claiming UK ministers have not given assurances they will not legislate in devolved matters.

Devolved ministers are also demanding answers from the UK Government on funding for the projects, claiming the Conservatives have been unwilling to guarantee that support for ports in Scotland and Wales would match amounts being offered in England.

But a UK Government source told the Herald that the accusations were “nonsense”.

Scottish Business Minister, Ivan McKee, said: “The Scottish Government remains committed to working in partnership with the UK Government, however we cannot sign up to a UK policy which does not respect devolution, undermines the Scottish economy and fails to provide equivalent funding to what is on offer for ports in England.

“UK ministers have failed to work with us to ensure their proposals best meet the needs of business and communities in Scotland.

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“Should the UK Government move forward with a proposal that does not include a commitment on fair work and net zero, the Scottish Government will not support this initiative.”

He added: “To ensure there is not a race to the bottom on workers’ rights and the environment, the Scottish Government will challenge any attempts by the UK Government to impose their model in Scotland by legislating in devolved areas, which would be a breach of the spirit of the devolution settlement.

“I would strongly encourage the Secretary of State for Scotland and other UK ministers to work with us to ensure we can deliver green ports in Scotland.”

In a letter to Scottish Secretary Alister Jack, Mr McKee acknowledged his counterpart has “accepted the principle that fair work and net zero can be included in the prospectus” for freeports, but a row has developed over the wording with the SNP minister claiming the Tories believe this “will make no substantive difference”.

Mr McKee added that Mr Jack has recognised that “having two designations rather than one fairly reflects the economy and geographical characteristics of Scotland” but warned the proposed funding arrangement is “unfair and disadvantages ports in Scotland compared to their competitors in England”.

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A UK Government source said: “This is nonsense. Rather than work constructively with us on creating much needed jobs in Scotland, the Scottish Government would rather waste time playing political games.”

The Welsh Government has again written to the UK Government asking for urgent talks, as there has yet to be a formal offer made for a freeport to be established in Wales.

Welsh Finance Minister, Rebecca Evans, said the UK Government is “pressuring the Welsh Government to redirect its resources to deliver a UK Government policy priority”.

A UK Government spokesperson said: "The UK Government is committed to bringing freeports to Scotland and Wales. It has huge potential to boost the Welsh and Scottish economies and create hundreds of highly skilled jobs.

"We know there is strong support from stakeholders, who are keen to see progress. We hope the Scottish and Welsh Government will decide to work with us on this.”