Prime Minister Theresa May will set out five "tests" for a future UK-EU deal and pledge to "bring our country together" in a major speech on Friday.
Prime Minister Theresa May has set out what she called "hard facts" about leaving the European Union, as she delivers her big Brexit speech.
The "deepest possible" free trade deal is achievable because it is in both EU and UK interests, she will argue.
"We are leaving the single market, life is going to be different," she told an audience at London's Mansion House.
She is expected to set out details of how the UK will seek to mirror EU rules in some areas and "diverge" in others.
Access to each others markets would be "less than it is now," she acknowledged.
A cabinet minister said she will also stress the UK "can't get everything we want" from Brexit talks.
But she added that the "jurisdiction of the European Court of Justice in the UK must end".
Transport Secretary and leading Brexiteer Chris Grayling told BBC Radio 4's Today programme Mrs May "will recognise it is not about cherry-picking".
Mrs May is outlining what the UK wants from its economic relationship with the EU after Brexit.
He said there would be "an awful lot of detail about how things would work" and Mrs May would set out a "very clear picture" of a post-Brexit economic relationship between the UK and EU.
She started by setting out five "tests" for the negotiations and pledge to "bring our country together".
Labour's Shadow Brexit Secretary Sir Keir Starmer said he wanted to see "specifics": "We've had vague assertions and we've had red lines and we've had sound bites and now we really need concrete answers."
She said both sides needed to accept that "neither side can have exactly what we want" but she was confident that an agreement can be found.
He said she "must deal with" how she plans to avoid a hard Irish border, after she said earlier this week that an EU proposal for a "common regulatory area" on the island of Ireland was unacceptable.
The PM said the deal on access to each other's markets had to be on fair terms - with the need for "binding commitments".
"I agree with her, it's simply not a road that we can go down but that really ramps up the pressure on her to say what then is the answer," Sir Keir said.
"For example, we may choose to commit some areas of our regulations like state aid and competition to remaining in step with the EU's," she said
Scotland's First Minister Nicola Sturgeon said on Twitter the PM's speech "must set out exactly how she intends to achieve her - seemingly contradictory and unachievable if we leave single market/customs union - objectives" and the time for "vacuous, meaningless rhetoric" was "long gone".
On the Northern Irish border, Mrs May said: "Our departure from the EU causes very particular challenges for Northern Ireland, and for Ireland.
"We joined the EU together 45 years ago.
"It is not surprising that our decision to leave has caused anxiety and a desire for concrete solutions. "
The UK is due to leave the EU on 29 March 2019 but it wants a transition period lasting around two years after that, intended to smooth the way to the future post-Brexit relationship between the UK and the EU.
The UK is due to leave the EU on 29 March 2019 but it wants a transition period lasting around two years after that, intended to smooth the way to the future post-Brexit relationship between the UK and the EU.
BBC assistant political editor Norman Smith said Mrs May was expected to "reach out" to the EU in the speech as part of a bid to get it to at least begin serious talks about a future trading relationship.
BBC assistant political editor Norman Smith said Mrs May was expected to "reach out" to the EU in the speech as part of a bid to get it to at least begin serious talks about a future trading relationship.
Mrs May's speech has been relocated from Newcastle to the Mansion House in central London, because of severe weather.
The speech has been relocated from Newcastle to the Mansion House in central London, because of severe weather.
'Take control'
She will pledge to bring the country back together "taking into account the views of everyone who cares about this issue, from both sides of the debate".
Analysis
By Laura Kuenssberg, BBC political editor
After more than a year of the UK government being accused of aiming for an unrealistic shopping list from Brussels, hoping for lots of cake and eating every last crumb, on Friday - to employ the exhausted metaphor - a member of the Cabinet told me it will feel like "Theresa May being honest with the public", complete with some "hard truths".
Read more from Laura
Mrs May is expected to set out five tests to guide the UK in negotiations:
She will say the EU referendum result was a vote to "take control of our borders, laws and money" but was "not a vote for a distant relationship with our neighbours".
And Mrs May will say the new agreement must endure so the UK and EU can "forge ahead with building a better future for our people".
'Unique starting point'
On the key issue of post-Brexit trade and the economic partnership, Mrs May will say: "I want the broadest and deepest possible agreement, covering more sectors and co-operating more fully than any free trade agreement anywhere in the world today.
"I believe that is achievable because it is in the EU's interests as well as ours and because of our unique starting point, where on day one we both have the same laws and rules.
"So rather than having to bring two different systems closer together, the task will be to manage the relationship once we are two separate legal systems."
Mrs May has ruled out continuing UK membership of the single market and customs union and European Council President Donald Tusk warned on Thursday that meant there could be "no frictionless trade" after Brexit.
Labour's Chuka Umunna, for Open Britain - which campaigns for close ties with the EU after Brexit - said Mrs May must "be honest with the people of our country about what the consequences of her hard Brexit policy are" for Northern Ireland.
"There is only one way to avoid a hard border in Ireland and to protect the Good Friday Agreement - that is for the whole of the UK to stay in the customs union and the single market."
