NICOLA Sturgeon has signalled a thaw in relations with Theresa May over Brexit, but said “substantial” progress is still required to avoid a constitutional crisis in the spring.

After a 45-minute meeting with the Prime Minister in Downing Street, the First Minister said she felt more hopeful of reaching agreement on the main Brexit legislation.

Ms Sturgeon has called the EU (Withdrawal) Bill a “power grab”, as it would see 111 devolved powers repatriated to Westminster when the UK leaves Europe – not to Holyrood.

She said the Scottish Parliament could still not give legislative consent to the Bill, as drafted, and that no agreement had been reached on fixing it.

But, in a striking change of tone, Ms Sturgeon also said the talks were “constructive and cordial” and she and Mrs May had “developed a better understanding of each other’s positions”.

After the two leaders last met eight months ago, Ms Sturgeon complained she had found it “impossible to get any human connection” with a cold and impersonal Mrs May.

Speaking to the media outside Number 10, Ms Sturgeon said: “I made very clear… that the Withdrawal Bill as it stands would not be acceptable and we would not be able to recommend approval of that. That remains the position.

“But, hopefully, having had the opportunity to air the concerns that we have in more detail, we will be able to see progress in the weeks to come.”

She added: “While we didn’t reach agreement, I think we developed a better understanding of each other’s positions. I made clear that the Scottish Government wants to find agreement on the Withdrawal Bill. We oppose Brexit but we understand withdrawal legislation is necessary, so we want to find agreement.

“I also made clear what our bottom lines are on that Bill. Discussions will continue and hopefully we can reach some points of agreement in the weeks to come.”

Ms Sturgeon also said Mrs May’s plan to include the exact day and hour of Brexit in the Bill was not “sensible”, as it would narrow room for manoeuvre in talks with the EU.

Downing Street said the PM told Ms Sturgeon that “it remains her priority to provide certainty to businesses and people both in Scotland and across the country, as well as protecting our UK internal market”.

Tory MSP Adam Tomkins said: “It’s clear there is a deal to be done on the return of powers which both respects devolution and protects the UK internal market.

“The Scottish Conservatives want to see both the UK and Scottish Governments make progress so we can get a Brexit deal for Scotland that can be supported by all parties.”

Shadow Secretary of State for Scotland Lesley Laird said: “Scotland is stuck between two obstinate governments, neither working in the best interests of the nation.

“The First Minister refuses to rule out a second independence referendum, while the Prime Minister is intent on a race-to-the-bottom Brexit which hoards power in Westminster.”