PM Rishi Sunak has been giving a statement in the House of Commons after unveiling a deal with the EU on post-Brexit trading arrangements in Northern Ireland
He says the deal "permanently removes any sense of a border in the Irish Sea"
Sir Keir Starmer says Labour will back the deal, which he says will improve the UK's international standing
Democratic Unionist Party leader Sir Jeffrey Donaldson says the deal secures "significant progress" but concerns remain
Earlier, Sunak and EU chief Ursula von der Leyen hailed a "decisive breakthrough" at a joint news conference
Sunak said the NI Assembly would be able to stop some EU laws on goods applying by using what he called a "Stormont Brake"
But Von der Leyen stressed this was an "emergency mechanism" and the European Court of Justice would have the final say on single market issues
The EU's Von der Leyen says her thoughts are with the family of Det Ch Insp John Caldwell, who was shot in Omagh on Wednesday.
Von der Leyen says the upcoming 25th anniversary of the Good Friday Agreement will mark an “important milestone” for people in Northern Ireland, and says “violence has no place in our society”.
Von der Leyen mentions two examples that she finds telling: she says the Windsor Framework says the same food will be available in Northern Ireland as in the rest of UK, and it will permanently enable medicines to be available in Northern Ireland at same time as the UK.
"We have agreed on strong safeguards that will protect the integrity of EU's single market," she says.
The Framework respects and protects our respective markets and interests, Von der Leyen says.
We had to listen to the people of Northern Ireland - EU chief
Von der Leyen says today "we can take pride in the fact we have delivered" on commitments made during the Brexit negotiations.
She says she and Sunak have reached an "agreement in principle on the Windsor Framework", calling it a "new chapter" for the UK and EU's relationship.
The EU chief goes on to acknowledge that she and Sunak covered and attempted to solve a vast range of issues during these talks.
Von der Leyen says it is an "honour and pleasure" to be in Windsor.
She says she and the PM are delivering on the "important commitment" they made a few months ago and was encouraged by their co-operation on the war in Ukraine.
But she says: "I also remember the two of us were honest with each other about the difficulties in our bilateral relationship and it was vital to put that on the right footing too."
Wrapping up his statement, the prime minister says the deal will preserve Northern Ireland's place in the UK "family of nations".
He says it will fix "practical problems" with the Northern Ireland Protocol.
He adds, however, that political parties will want to consider the detail, a process that will require “time and care”.
As we know the Democratic Unionist Party have been boycotting power-sharing in Northern Ireland over the Protocol.
The third part of deal has to do with safeguarding sovereignty for the people of Northern Ireland, Sunak says.
He adds that many people in NI are worried about being subject to changes in EU goods laws.
To address that, today's agreement introduces a new Stormont brake, allowing the Northern Ireland Assembly to not only to have a say over these laws but also stop them from applying in Northern Ireland, Sunak says.
"This establishes a clear process for which the democratically elected assembly can pull an emergency brake" for changes affecting EU goods that have an impact on everyday life. If the brake is pulled, the UK government will have a veto, he says.
This gives the Good Friday Agreement - a political deal which helped end decades of conflict in Northern Ireland known as the Troubles - a "powerful new safeguard", Sunak says.
Sunak goes on, listing the second part of the new deal, which he says will make things feel more equal in the UK and Northern Ireland.
"We have protected Northern Ireland's place in the Union," he tells reporters gathered in Windsor, saying the new deal ensures that the same "quintessentially British" products will once again be available in Northern Ireland.
This includes trees and seeds in garden centres, he says.
Today's agreement also delivers a landmark settlement on medicines, he continues, adding drugs approved for use by the UK regulator will automatically become available in Northern Ireland.
The PM says they have made three big steps forward with this agreement.
He says there will be a "smooth flow of trade within the UK", with goods separated into a green lane - for goods travelling to Northern Ireland - and a red lane - for goods at risk of moving into the EU.
He says in the green lane, "burdensome customs bureaucracy will be scrapped".
"We have removed any sense of a border in the Irish Sea," he continues.
Nick Eardley
Chief political correspondent
Rishi Sunak is making this point primarily about making the situation better for people in Northern Ireland.
He is convinced it will make trade easier and remove some of the “challenge” we’ve seen.
Crucially, he argues this means no border in the Irish Sea.
Will the DUP agree? Remember they’re not the only party at Stormont who will deliver a verdict, but theirs will be crucial in deciding whether power-sharing at Stormont resumes.
Sunak says today's agreement marks a "new chapter" in the UK's relationship with the EU.
The deal, he says, will preserve the "delicate balance" in the 1998 Good Friday Agreement that protects the "aspirations and identity" of all people in Northern Ireland.
It will "end the uncertainty" for people in Northern Ireland, he adds.
Sunak says today's agreement delivers smooth-flowing trade within the whole of the UK, protects Northern Ireland's place in the union, and safeguards sovereignty for the Northern Irish.
He also pays tribute to Von der Leyen and her "vision" that allowed a "new way forward".
Rishi Sunak gets things started, saying all our thoughts are with Det Ch Insp John Caldwell, the police officer who was shot last week in Omagh.
The UK prime minister goes on to say he welcomed Ursula von der Leyen to Windsor, and they've now made a "decisive breakthrough" in deciding a post-Brexit agreement for Northern Ireland.
He says they have changed the original protocol and it will now be known as the Windsor Framework.
The press conference with European Commission president Ursula Von der Leyen and PM Rishi Sunak is under way.
You can watch it on the BBC News channel or at the top of this page.
Shane Harrison
BBC NI Dublin correspondent
Will this time be different?
That’s the unspoken thought many people in the Republic of Ireland will be thinking now that news of another UK-EU Brexit-related deal has been reached.
Twice before a British Tory government has sought to renege on a deal that it had negotiated.
But this time there is more confidence that it will be third time lucky.
Image source, PA MediaTaoiseach Leo Varadkar travelled to Belfast in January to hold protocol talks with the Stormont parties
More than any other EU state, Ireland - which shares a land border with Northern Ireland and the UK - wants a deal on the Northern Ireland Protocol to stick, with a restoration of the Good Friday Agreement institutions.
But will that happen?
All eyes south of the border will now turn to the DUP.
Their reaction to the deal will be the key to any return of devolution.
Jessica Parker
Brussels correspondent
You can tell the timing and choreography of all this has been tightly coordinated on both sides of the Channel.
As we got news a deal was done, senior European Commission officials headed to brief the 27 member states about the agreement. They may even present them with the legal text.
EU countries have ambassadors stationed in Brussels in order to keep across negotiations and policy areas across a vast range of issues.
And this is a special meeting of those ambassadors who’ll want to pore over the detail of the EU-UK agreement. However, no major resistance is expected.
European Commission president Ursula Von der Leyen and PM Rishi Sunak have arrived at the venue for the press conference in Windsor.
It's due to start in about five minutes. Stay with us.
Image source, AFPIf you're just joining us - the UK and EU have reached an agreement over the future trade status of Northern Ireland. But there are a number of unknowns - and the issue has been a contentious one ever since the UK voted to leave the EU back in 2016.
Here's more detail on what's been happening - and what next.
Jon Tonge, a professor of British and Irish politics at the University of Liverpool, has been talking to our colleagues on the BBC News channel in the last half an hour.
He describes the news that Rishi Sunak and Ursula von der Leyen have reached a deal over Northern Ireland as a "huge breakthrough" for the UK prime minister.
Tonge also stresses that this is much different to the "oven-ready" protocol Boris Johnson claimed he had years ago.
"It's quite clear that the EU has moved substantially" on areas that it previously wouldn't, he continues, referencing things such as state aid for Northern Ireland.
What happens now? Well, Tonge says, the deal still needs to pass the real test: getting the Democratic Unionist Party's (DUP) approval.
Chris Mason
Political editor
The deal is done and the stage is set.
Here’s how it’s looking as reporters arrive for the news conference expected shortly with the prime minister and the president of the European Commission.
Nick Eardley
Chief political correspondent
The two leaders have signed on the dotted line. Now comes the hard sell.
Rishi Sunak and Ursula von der Leyen will take part in a press conference at 15:30 GMT to set out their arguments for the deal.
You can expect the PM to argue it will make trade easier for Northern Ireland and protect its place in the UK. There is confidence in government that they have got a good deal out of Brussels.
The PM will then head back to Westminster where he'll make a statement to Parliament. He will be trying to persuade the DUP and his own backbenchers of the merits.
Both are waiting to see specifics in a legal text.
I'd expect some documents today - but it may be a few days before the DUP and Brexiteer Tories scrutinise it fully.