General election 2017: Labour vows 'radical' devolution extension
Labour has pledged to introduce a "radical extension of devolution" after Brexit if it wins the forthcoming general election.
The party's shadow Brexit secretary, Sir Keir Starmer, said powers transferred back from Brussels should go straight to the relevant devolved body.
This would include Holyrood, he said.
The UK government has already said the Scottish Parliament will have "significant new powers" after Brexit.
The Great Repeal Bill will see thousands of EU laws on everything from workers' rights to the environment scrapped or replaced with UK equivalents.
But the UK government has not yet said which of these new powers will be kept at Westminster, and which will devolved to other parts of the UK - including Scotland - after the UK leaves the EU.
The Scottish government has repeatedly accused the prime minister of planning a "power grab" because she has not confirmed that all of the powers associated with devolved areas, such as fishing and agriculture, will be handed to Holyrood once they return from Brussels.
In a speech setting out Labour's vision for a post-Brexit Britain, Sir Keir said the party's manifesto would commit to "a presumption that any new powers that are transferred back from Brussels should go straight to the relevant devolved body".
He added: "This will apply to regional government across England, as well as to the devolved administrations in Scotland, Wales and Northern Ireland.
"This was a proposal included by the Mayor of London in his Brexit White Paper and it is one a Labour government will take forward.
"A Labour approach to Brexit will be part of a radical extension of devolution, and will help bring the country together."
Sir Keir also said Labour would scrap the prime minister's Brexit plans and unilaterally guarantee the rights of EU residents before talks start.
And he said Labour wanted a deal which prioritises jobs and workers' rights, that migration rules had to change and that the EU single market should be kept "on the table".
Analysis by Nick Eardley, BBC Scotland political correspondent
When the UK leaves the EU, significant powers will come back from Brussels.
There's been a row for months about where they go.
The Scottish government believes those covering devolved areas - like agriculture and fisheries - must come to Edinburgh. Nicola Sturgeon has suggested anything else would be an attack on devolution.
Labour has suggested it will do that today. Presuming powers come back doesn't mean they automatically will - but Keir Starmer says his party will oversee a "radical extension of devolution" if it's in government.
This pledge goes further than the Conservatives have so far. The current government says more powers will come to Holyrood - but hasn't specified what they'll be.
That's because they think there may be a need for UK-wide frameworks in some areas.
Speaking in the House of Commons in March, Scottish Secretary David Mundell gave an "absolute guarantee" that the Scottish Parliament would get more powers as a result of Brexit.
And Prime Minister Theresa May said the UK government was discussing with the devolved administrations "the whole question of the UK framework and devolution of issues as they come back from Brussels".
She added: "The overriding aim for everything that we do when we make those decisions is making sure that we don't damage the very important single market of the UK - a market that is more important to Scotland than the EU is."
'Weak and divided'
But Ms Sturgeon told Holyrood on 30 March that the Scotland Act meant the powers should "automatically come to this chamber".
She said nobody in the UK government, including during her talks with the prime minister, had given her that guarantee.
The first minister said this "leads me to suspect that what the Tories are actually planning is a power grab on this parliament, and that will be absolutely unacceptable".
Responding to Sir Keir's speech, SNP MP Stephen Gethins said Labour had handed the Conservatives a "blank cheque" on Brexit.
He added: "'Labour are weak and divided, and the mixed messages from them on Europe is clearly one of the reasons the Tories have been allowed to get away with their disastrous Hard Brexit."
The UK government's Brexit secretary, David Davis, said that Labour leader Jeremy Corbyn was "too weak and floundering to get a good deal in the Brexit negotiations".
He added: "A divided Labour Party, propped up by a Liberal Democrat/SNP coalition of chaos, can't even agree amongst themselves on Brexit. Putting this chaotic team in charge of negotiating with the EU would be a dangerous risk to Britain's future."
The Liberal Democrats said Labour was "failing the people" by not supporting another EU referendum, saying its Brexit plan had "more holes than a colander".