Theresa May will gamble this week by siding with Eurosceptics and signalling she is prepared to take Britain out of the single market and customs union.
In her most significant Brexit speech since taking office, the Prime Minister will defy critics by indicating she is open to a clean break with the EU.
The intervention, which follows immense pressure to reveal her Brexit plans, is designed to reassure the public and reveal what she wants from talks.
However the speech risks exposing deep splits in the Tory Party over Europe as she finally details her vision for Britain’s future outside the EU.
In her speech, Mrs May is expected to say that Britain must
Be prepared to leave the customs union to secure free trade deals across the world.
Regain full control of its borders even if that means ending single market membership.
No longer be bound by European Court of Justice rulings after Brexit, despite claims to the contrary.
Unite after the “division” of the referendum by ditching the terms “Leaver” and “Remainer”
Contents of the speech are being closely guarded by Number 10, with a draft yet to be circulated senior cabinet ministers.
However sources familiar with the Prime Minister’s thinking have told The Telegraph she will indicate support for many Eurosceptic demands.
“She’s gone for the full works. People will know when she said ‘Brexit means Brexit’, she really meant it,” a government source said.
The comments are likely to trigger a backlash from pro-EU figures who will warn the Prime Minister has picked a “hard Brexit” over protections for the economy.
However they will be cheered by Eurosceptics who argue that only the cleanest break with the EU can fulfill what the public wanted when they voted for Brexit.
It comes after the EU’s chief negotiator of Brexit gave the first indication of a softer stance as he conceded the Continent needs to retain access to the City of London.
Michel Barnier privately told MEPs that he wanted a “special” relationship between the 27 remaining EU countries and Britain’s financial centre after Brexit.
Tory MPs said it showed that “commercial self-interest is overtaking mere politics” among EU leaders concerned about the financial implications of cutting themselves off from London.
Mrs May’s speech, to be delivered on Tuesday, has been months in the making and is designed to update the public on what she wants from Brexit talks.
In front of a crowd of diplomats at London’s Lancaster House – a 19th century state building synonymous with Britain’s global past – she will outline her Brexit priorities.
She is expected to discuss whether Britain will remain in the European single market, which allows free trade across the bloc, and customs union, which lets goods move across borders without customs checks.
Numerous government sources have told this newspaper that Mrs May will indicate Britain is prepared to be outside both, while seeking to replicate elements of the arrangements in a bespoke deal.
Earlier this week the Prime Minister said she wanted to sign a free trade deal with New Zealand and there are hopes for a similar agreement with America, India and many other countries.
“If you want to sign those kind of deals as soon as possible you can’t be in the customs union,” a Whitehall source said. The customs union effectively forbids countries from signing their own trade deals.
Foreign diplomats have also been told by ministers in recent weeks that they should expect the country to be outside the customs unions after Brexit.
In its place, Mrs May is expected to seek a new customs arrangement that preserves the benefits of the union, specifically no checks when goods cross the border.
Similarly by leaving the single market, the country would no longer be bound by European Court of Justice rulings and could limit EU immigration.
Both have already been named as priorities for Brexit talks by Mrs May and are unlikely to be granted by Brussels if the UK were to stay in the single market.
The speech is likely trigger a backlash from business figures concerned about higher tariff barriers and the impact on the Northern Ireland border.
However Eurosceptics – who have sought to define the position as “clean Brexit”, meaning cutting most ties with the EU, rather than “hard Brexit” – will cheer the move.
A report from the think tank Policy Exchange published on Monday endorses leaving the customs union, noting that 85 per cent of the world economy will soon be found outside the EU.
Figures in Number 10 believe David Cameron made a tactical mistake by asking for so little when he renegotiated Britain’s EU membership before the referendum.
Boris Johnson, the Foreign Secretary, and David Davis, the Secretary for Exiting the EU, have been closely involved in crafting the speech.
Mr Johnson saw the Prime Minister on Tuesday while Mr Davis has been in regular contact, though neither are understood to have seen the final draft.
Mrs May and her closest aides were said to be working on the speech throughout the weekend and will reveal their contents to Cabinet on Tuesday.
According to a trail of the speech, Mrs May will put unity “at the heart” of her vision as she calls on the nation to heal the divide created by the referendum.
“One of the reasons that Britain’s democracy has been such a success for so many years is that the strength of our identity as one nation, the respect we show to one another as fellow citizens, and the importance we attach to our institutions means that when a vote has been held we all respect the result,” Mrs May will say.
She will add: “The overwhelming majority of people – however they voted – say we need to get on and make Brexit happen.
“Business isn’t calling to reverse the result, but planning to make a success of it. And the House of Commons has voted overwhelmingly for us to get on with it too.
“So the country is coming together. Now we need to put an end to the division and the language associated with it – Leaver and Remainer and all the accompanying insults – and unite to make a success of Brexit and build a truly Global Britain.”