BRITAIN is now in the grip of a deepening constitutional crisis which may see the unelected House of Lords blocking Theresa May’s flagship Brexit Bill, Michael Russell has suggested.

Ahead of today's first debate by peers on the EU Withdrawal Bill, the Scottish Government’s Brexit Minister last night briefed them about Edinburgh’s concerns over a Whitehall “power-grab” but denied this was the SNP leadership trying to stir up further trouble for the Prime Minister and her colleagues, who are in the midst of a Tory civil war on Brexit.

Acknowledging how the Nationalists regard the second chamber as an affront to democracy and so have no representation there, Mr Russell said, nevertheless, such was the SNP administration’s determination to get the legislation amended, “we will sup with the devil himself to get it changed; not that I’m saying their lordships are the devil...but it will be a first for me, I have to say”.

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Asked if the country was now facing a constitutional crisis, he replied: “We are in one and have been in one for some considerable time. But it is deepening now. Unless there is an amendment, there won’t be a Legislative Consent Motion[LCM] and the corollary of that[is]…a Continuity Bill.”

But he went further as it emerged that Labour peer George Foulkes is to table an amendment, saying that unless the Scottish Parliament and Welsh Assembly give their consent, then peers should block the bill.

Mr Russell noted: “It might be a reasonable position for the peers to take; that in those circumstances the bill should not[pass]…The purpose of an LCM applies to certain parts of the bill. The convention would be those parts are removed; if those parts are not removed, then the peers might take the view the bill is not valid. That would be a logical position.”

But as the political rhetoric over a constitutional crisis between London and Edinburgh increased, Whitehall insiders appeared relaxed.

One senior source told The Herald: “There is no constitutional crisis. We are in the middle of a process and we’re optimistic we will get a satisfactory outcome.”

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He pointed out how the UK Government “recognised and appreciated” the constructive approach Mr Russell was taking on the issue. “His preferred option is to work with us to get a bill into such a state that satisfies everybody,” the insider added.

The Scottish Brexit Minister said he had been “very heartened” by peers who had been in touch with the Scottish Government, agreeing that the bill as it stood was “not fit for purpose”.

Lord Steel, the former Holyrood presiding officer, said: "Given the SNP has no representatives in our legislative chamber, I have been in touch with their Brexit Minister, Michael Russell, to say that I shall put forward the complaint about the bill currently dragging EU powers back to Westminster rather than Edinburgh."

The former Liberal Party leader stressed this was the view "not just of the SNP but of the Scottish Parliament as a whole".

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Lord Foulkes explained that he was tabling his amendment because of the “huge impact” the legislation would have on the devolved nations.

“They should not just be consulted, they should have a deliberate say; a real say in it. It would, therefore, be appropriate but also ironic for the unelected House to give power to the elected assemblies across three countries of the UK,” added the former Scotland Office Minister.

In other developments:

*the EU27 agreed its proposals for the next phase of talks on the transition period, saying that the UK will have to obey the EU rule-book in full for around two years after Brexit. Downing Street pointed out how there were “differences” between how London and Brussels were approaching the Phase 2 talks.

*sources close to Ruth Davidson said the Scottish Conservative leader was urging colleagues to stop the in-fighting on Brexit and “come together, focus on the day job and deliver for Britain”. Today, the Edinburgh MSP will give a speech on EU withdrawal when she will call for the row over devolution and the Brexit bill to be resolved quickly so that UK ministers can “talk about more than process”.

*the Commons Foreign Affairs Committee in a report today said Britain's diplomatic network in Europe was “too thinly stretched” and must be boosted to cope with the demands of Brexit. In particular, they said there was a need for representation at embassies in Berlin and Paris to be significantly increased.

*Labour supporters of close ties with Europe issued a challenge to Jeremy Corbyn to "get off the fence" and commit to keeping Britain in the single market and customs union after Brexit. They challenged what they claimed were "myths" being spread by the so-called "Lexit" lobby, which campaigns for Britain to leave the EU on left-wing grounds.