The devolved governments said that while they were committed to working with the UK government, UK ministers have signalled their intention to move forward without devolved consent and have failed to provide assurances they will not legislate in devolved areas.

Ministers said they are also seeking urgent clarity from the UK government on joint decision-making and funding allocations, as UK ministers have been unwilling to guarantee that funding for ports in Scotland and Wales would match amounts being offered in England.

The Scottish government said it has been trying to work with the UK government to ensure the UK freeport proposal reflects the needs of businesses and communities in Scotland. Adapting UK government proposals, new Scottish green ports would aim to offer a package of assistance to businesses that adopt fair work practices and contribute to Scotland’s just transition to a net zero emissions economy.

The Welsh government has again written to the UK government asking for an urgent discussion on how they can take these plans forward given there has yet to be a formal offer made for a freeport to be established in Wales.

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. 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.

“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.”

Welsh finance minister Rebecca Evans said: “We have consistently attempted to engage constructively with the UK government and reach agreement on a way of implementing freeports in Wales which is consistent with our priorities and values as a government.

“The UK government is pressuring the Welsh government to redirect its resources to deliver a UK government policy priority. This approach is unacceptable to us, and we have made clear that the UK government needs to demonstrate the same level of financial commitment to freeports in Wales as they have in England.”

Welsh economy minister Vaughan Gething said: “As a responsible government, we need to see that freeports demonstrate value for money. We also need to have confidence that the potential negative impacts of the UK government’s approach are mitigated.

“We recognise that without our support, a Welsh freeport would be less attractive and less competitive than those in England, but the UK government’s continued refusal to engage constructively suggests that they would rather risk undermining devolution by implementing a flawed freeport without our support than work with us to deliver benefits for Wales.”