Brexit talks between the Scottish and Welsh first ministers and Theresa May have broken up without agreement.

Nicola Sturgeon said the issues outstanding over legislation that transposes EU law into UK law once Britain leaves are "not insignificant" and warned there was now "real urgency" to reach a deal.

Lack of agreement from Edinburgh and Cardiff would not prevent the EU (Withdrawal) Bill from passing but forcing it through without consent could spark a constitutional crisis within the UK.

Speaking in Downing Street, the First Minister said: "There was certainly an indication on all sides that we want to reach agreement."

"We can't have our powers restricted or reduced without the consent of the Scottish Parliament," she told reporters.

Ms Sturgeon added: "The issues that remain between us are not insignificant but neither are they insurmountable."

She said the UK Government's concern was that Scottish Parliaments or governments could withhold consent unreasonably "and there is discussion to be had to give assurances that wouldn't be the case".

"It's a matter of trust," she said, but added: "We are having to trust the UK Government a lot in terms of other matters associated with the Brexit discussions.

"This is about protecting our principles, it's not about compromising on the principle, it's about finding compromise that allows the UK Government to abide by that principle, as I think they should, but have some of the concerns that they have got about that addressed and allayed."

The row centres on where devolved powers currently held by Brussels will be exercised once the UK quits the EU - with the Prime Minister claiming ahead of the talks that the "vast majority of powers returning from the EU" will go to Edinburgh and Cardiff.

However, the UK Government argues some powers must come first to Westminster so common frameworks can be established across the UK.

Downing Street said the leaders discussed the amendment that has been tabled that would "ensure the vast majority of devolved powers will transfer directly to Edinburgh, Cardiff and Belfast".

A spokesman said the Prime Minister "made clear her commitment to a deal that works for the whole of the UK and protects the security and prosperity of all our communities".

Meanwhile, the Scottish Government's emergency Brexit legislation has passed its second stage at Holyrood after 11 hours of scrutiny.

Brexit minister Mike Russell offered concessions on the controversial issue of giving Scottish ministers the power to keep pace with European Union regulations post Brexit.

The legislation had originally proposed these last up to 15 years - an initial five years and two possible extensions of the same length.

However, Holyrood's Finance and Constitution Committee voted to reduce this to a maximum total of five years - an initial three years after Brexit with two one-year extensions then permissible.