A CONSTITUTIONAL crisis now appears inevitable after it was reported that Theresa May would give no more ground to Scotland in Brexit Bill negotiations.

According to reports in the Herald, Whitehall sources say the UK Government will go “no further” in the power grab negotiations over fears that Scottish ministers might, among other things, kibosh plans to allow the Americans to sell chlorinated chickens.

Of all the responsibilities currently held by Brussels to be repatriated to the UK after Brexit, there are 111 in areas devolved to the Scottish parliament.

Initially the UK government wanted all to go back to London, and UK ministers would then decide which should be handed down to the devolved parliaments in Edinburgh and Cardiff and which should be part of a UK wide framework.

That was described as a “blatant power grab” by the Scottish and Welsh First Ministers.

Now, after much negotiation, there is agreement on 86 of those powers.

But unless there is consensus on the remaining 25 then the Scottish Parliament will almost certainly refuse to give the Withdrawal Bill consent, and will likely pass their own Continuity Bill.

While that can’t legally stop Brexit, it will spark an unprecedented constitutional crisis.

The Herald’s source said the UK Government wouldn’t agree to changes that would effectively allow Scottish ministers veto on changes to commons frameworks agriculture, fishing and environmental protection.

The source said: “I don’t sense us moving from our position. We have already moved a hell of a long way and we can’t move any further in the way the Scottish Government want us to.

“We’re still talking and officials are working hard to find a way through, but I don’t know whether we can now bridge that gap.”

If the UK Government were to formalise a free trade agreement with the US, it may mean compromising strict food safety standards that are in place in part because of EU regulations.

This could mean the UK having similar food regulations as the US, where the law allows lower animal welfare standards.

One of the most prominent examples is practice of keeping chickens crammed together, with little light and ventilation, which risks the chance of disease and infection. At the end of the process the birds' carcasses are washed with chlorine.

EU law means the birds' have a legal minimum amount of space, lighting and ventilation. While that’s more expensive for farmers, it means far fewer sick chickens.

One in seven of the US population contracts a food-borne illness every year at present, compared to just over one in 70 in the UK.

Talks between Scottish Brexit secretary Michael Russell and May’s de facto deputy, David Lidington, are due to resume on Thursday.

The Prime Minister and the First Minister will meet the week after.

Labour’s Neil Findlay said the Tories were “sleepwalking towards a constitutional crisis with their shambolic handling of this issue”.

The party’s Holyrood Brexit spokesman said: “There is a clear lack of leadership on the part of the Tories – David Mundell has been banished from any discussions by the Prime Minister and Ruth Davidson has simply looked the other way while her own party tramples all over the devolution settlement.”

He called on the Scottish government to publish the areas of dispute “so the Scottish public can understand why their two governments are unable to reach a compromise.”

MSPs are due to begin scrutiny of the Scottish Government's continuity bill in parliament today.

Members of the Delegated Powers and Law Reform Committee will be the question Brexit minister Mike Russell on the legislation – which Presiding Officer Ken Macintosh has already ruled to be outside of Holyrood's legislative competence.

Last week Tory constitution spokesman, Adam Tomkins, described the bill as "unnecessary" as a "fix [was] within reach" to make the EU Withdrawal Bill "fit for purpose".