The UK Government is "threatening to strip the Scottish Parliament" of some of its powers, the First Minister has claimed.

Nicola Sturgeon used a speech at the David Hume Institute on Tuesday evening to launch accusations and criticism towards the UK Government and members of the Conservative party.

The First Minister said there is currently a "Westminster faction" which views the UK's exit from the EU as "an opportunity to rein in the Scottish Parliament".

Sturgeon has levelled the accusations at Downing Street despite the UK Government already pledging in its Brexit white paper "that no decisions currently taken by the devolved administrations will be removed from them and we will use the opportunity of bringing decision making back to the UK to ensure that more decisions are devolved."

The SNP leader also talked up the need for a second independence referendum if common ground between both governments cannot be found.

Responding, the UK Government said the First Minister's claims "completely misrepresented" their position.

Sturgeon said: "Far from the promises of the Leave campaign that a Brexit vote would automatically see swathes of new powers repatriated from Brussels to Holyrood, the Tories are actually threatening to strip the Scottish Parliament, and the other devolved administrations, of some of their powers.

"It is clear from their statements that even elements of farming and fishing policy - which have been a wholly devolved competences from day one - now risk being taken back to Westminster.

"That would be utterly unacceptable. It would be a gross betrayal of the claims and promises made during the EU referendum campaign.

The First Minister added: "And more profoundly it would fundamentally undermine the basis of the existing devolution settlement.

"So what we have is in effect an attack on the very foundations of the devolved parliament we voted for 20 years ago.

"It is being made by a UK Government which speaks the language of partnership but which in reality pays scant if any heed to Scotland's democratic voice. The question we face, is how to respond to it."

Sturgeon also claimed Scottish "values and priorities" are "threatened" by the UK Government's approach to Brexit.

The SNP leader also talked up the need for a second independence referendum if Downing Street does not alter its approach to Brexit.

She told the audience: "If those circumstances arise, proposing a further decision on independence wouldn't simply be legitimate, it would almost be a necessary way of giving the people of Scotland a say in our own future direction.

"It would offer Scotland a proper choice on whether or not to be part of a post-Brexit UK - a UK that is undoubtedly on a fundamentally different path today than that envisaged in 2014.

"And in the absence of compromise from the UK Government, it may offer the only way in which our voice can be heard, our interests protected, and our values upheld."

Scottish Conservative leader Ruth Davidson said: "The UK Government's white paper on Brexit makes it very clear that no decisions currently taken by devolved administrations will be removed and that when powers are returned from Brussels, more decisions will be devolved.

"This hyperbole from the First Minister takes synthetic grievance to a whole new level. Frankly, she sounds shrill.

"Nicola Sturgeon's attempt to use Brexit to manufacture the case for a second referendum has quite simply failed.

"She should now take it off the table so Scotland and the UK can work to get the best Brexit deal possible."

Scottish Labour leader Kezia Dugdale said: "This is ridiculous scaremongering from Nicola Sturgeon.

"The Scottish Parliament has major new powers over tax and welfare, which the SNP simply refuses to use."

A UK Government spokesman said: "These claims completely misrepresent the UK Government's position.

"We have been very clear that no decisions currently taken by Holyrood will be taken away.

"We have also said that we will use the opportunity of bringing decision-making back to the UK to ensure that more decisions are devolved.

"As a result of the Scotland Act passed last year, Holyrood is becoming one of the most powerful devolved parliaments in the world.

"The only threat to devolution is the policy of taking Scotland out of the United Kingdom."