The Prime Minister will set the clock ticking on the UK’s departure from the EU via a letter to European Council president Donald Tusk, before making a statement to the House of Commons at lunchtime.
She will tell MPs she intends to represent every part of the United Kingdom and all its inhabitants – including EU nationals whose continued rights beyond Brexit she has refused to guarantee – throughout the two-year negotiating window.
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And May will call for those on both sides of the referendum debate to unite behind the government through the process.
The prime minister has insisted she would be willing to walk away from talks if there is a “bad deal” on offer, but Labour leader Jeremy Corbyn has warned the prime minister it would be a “national failure of historic proportions” if she fails to negotiate a trade arrangement that secures the UK’s economic prospects.
Before the letter is delivered to Tusk by Tim Barrow, the UK's Permanent Representative to the EU, May will chair a special Cabinet at 8am.
After the Scottish Parliament voted in favour of a second independence referendum, the prime minister will use her Commons statement to state her “fierce determination to get the right deal for every single person in this country”.
“As we face the opportunities ahead of us on this momentous journey, our shared values, interests and ambitions can – and must – bring us together,” she will say.
“We all want to see a Britain that is stronger than it is today. We all want a country that is fairer so that everyone has the chance to succeed.
“We all want a nation that is safe and secure for our children and grandchildren. We all want to live in a truly Global Britain that gets out and builds relationships with old friends and new allies around the world.
“These are the ambitions of this government’s Plan for Britain. Ambitions that unite us, so that we are no longer defined by the vote we cast, but by our determination to make a success of the result.
“We are one great union of people and nations with a proud history and a bright future.
“And, now that the decision has been made to leave the EU, it is time to come together.”
TRANSFORM
Corbyn put out his own statement ahead of the UK embarking on what he called the “country’s most important negotiations in modern times”.
“The British people made the decision to leave the European Union and Labour respects that decision,” he said.
“Britain is going to change as a result. The question is how. The Conservatives want to use Brexit to turn our country into a low wage tax haven. Labour is determined to ensure we can rebuild and transform Britain, so no one and no community is left behind.
“It will be a national failure of historic proportions if the prime minister comes back from Brussels without having secured protection for jobs and living standards.
“That's why Labour has set the clear priorities of full access to the European market, rights at work and environmental protection. And we will hold the government to account every step of the way.”
Tusk is expected to give an initial response to the Prime Minister’s letter within 48 hours, but the 27 other EU member states will wait until a meeting on 29 April to discuss their priorities for the negotiations.
Reciprocal guarantees for EU citizens in the UK and British nationals living in the EU, the UK’s “divorce bill” to cover its liabilities and commitments, and the situation in Northern Ireland are expected to be among the first items on the agenda for the talks.
As the Article 50 letter was sent, the Public and Commercial Services union warned the civil service was woefully understaffed to deliver Brexit.
General secretary Mark Serwotka said “it is clear to everyone that the civil service is woefully understaffed and underprepared for Brexit”.
He added: “While we engage in the long, complex process of withdrawal from the EU, there will be no let-up in the demand for existing services. All cuts plans must be halted immediately to allow us to properly discuss the staffing and resources that are needed.”