NICOLA Sturgeon has warned Theresa May that it is now “very likely” Holyrood will withhold its consent to the UK Government’s flagship Brexit Bill.

Yesterday, Cabinet Office Minister David Lidington said the "vast majority" of returning EU powers would now start in Edinburgh, Cardiff and Belfast rather than at Westminster. No 10 claimed the move was a “considerable offer”.

The Prime Minister’s effective deputy said Westminster would only be involved where a "pause" was needed to draw up UK-wide frameworks. Whitehall wants a “safety brake” on 25 of the 111 powers and responsibilities to avoid any divergence of policy before common UK-wide frameworks can be agreed on areas such as agriculture and fisheries.

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But the First Minister and her colleagues believe this continues to be a “power-grab” by Westminster.

Ms Sturgeon, who is due to give a keynote speech at the ABI insurance industry conference in London this afternoon, said she accepted that in some cases there would need to be common systems of regulation but stressed they needed to be agreed between the UK Government and the devolved administrations and should not be imposed by Westminster.

She told BBC Radio 4’s Today programme: "We are simply trying to protect the powers that the Scottish Parliament already has; things like agriculture, fishing, environmental policy, food standards, justice, health.

"These are all currently responsibilities of the Scottish Parliament. At the moment, we have to exercise those powers within the confines of European law.

"But after Brexit, in terms of the devolution settlement, those powers should return to the Scottish Parliament and it should be up to us how we exercise,” argued Ms Sturgeon.

She went on: "I will not sign up to something that effectively undermines the whole foundation on which devolution is built and no first minister, no Scottish Government worth its salt, should do so."

Asked how likely it was that Holyrood would withhold its consent, the FM replied “very likely”.

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Time is now running out as Mrs May has until March 22 to table her amendment to Clause 11 of the EU Withdrawal Bill. Another Joint Ministerial Committee is due in the next few days and a plenary session in Downing Street, chaired by Mrs May, is also expected before the March deadline.

Any failure to secure MSPs’ consent would create a constitutional crisis as the only way the UK Government could proceed with its flagship bill would be to override the will of the Scottish Parliament