Investment fund manager Gina Miller, who brought the case against the government, said "no prime minister, no government can expect to be unanswerable or unchallenged - Parliament alone is sovereign".

She says the judgement means MPs will be able to bring their "invaluable experience and expertise" to help the government select the best course in its Brexit negotiations.

"There's no doubt that Brexit is the most divisive issue of a generation but this case was about the legal process and not politics," she said.

Ms Miller added that she was shocked "by the levels of personal abuse" she had suffered "for simply bringing and asking a legitimate question".

She finished by saying she sincerely hoped that people who stand in positions of power and profile "are much quicker in condemning" those who cross the line of human decency.

Image source, Reuters

The pound has dropped slightly after the government lost its Supreme Court appeal on whether Parliament must vote on starting the Brexit process.

The pound is 0.6% lower against the dollar at $1.246. Before the judgment sterling was above $1.25 at a five-week high. 

Against the euro, sterling is 0.3% lower at €1.160.

Reality Check

How long will it take?

The government wanted to trigger Article 50 using the Royal Prerogative, which is a set of powers that used to be held by the monarch but now reside with government ministers.

That would have meant it could have done so at a time of its choosing and without consulting Parliament at all.

The decision that it must specifically pass a bill is significant. Some other procedures would have meant fewer stages in Parliament and no chance to make amendments.

A full bill means that both houses of Parliament must agree and amendments are possible.

To become an act of Parliament a bill must pass several stages in both the Commons and the Lords. That often takes months of debate, but it doesn't necessarily have to. Emergency legislation can be passed within a single day if everyone agrees it is urgent.

The bill to trigger Article 50 won't be that quick, but it needn't take too long. For one thing, it is likely to be a very short bill with only one or two clauses.

How much opposition?

Labour leader Jeremy Corbyn has said that his MPs should not seek to block Article 50. Ken Clarke is expected to be the only Conservative who will vote against it. So the numbers look to be in place to ensure a smooth passage for the bill in the House of Commons.

But more MPs may back attempts to amend the bill, for example, by adding conditions about the sort of Brexit the government should negotiate.

In principle, the House of Lords could be different. The government does not have a majority and many peers remain strongly opposed to Brexit.

However, there is recognition that Parliament voted overwhelmingly to hold a referendum and that the referendum delivered a clear, albeit close, result. Members of the House of Lords, who are not elected, realise that any attempt to frustrate Brexit could be regarded as undemocratic.

David Green, a solicitor for hairdresser Deir Tozetti Dos Santos, said the Supreme Court had decided that the rights attached to the UK's membership of the EU were given by Parliament and can only be taken away by it.

He hailed today's ruling as "a victory for democracy and the rule of law and we should all welcome it".

He said Theresa May's decision to allow Parliament a vote was "insufficient" but was only brought about by the Supreme Court case.

Supreme Court president Lord Neuberger, in giving its ruling, said although the government lost the challenge, the justices unanimously ruled that there was no need to consult with the devolved powers in Scotland, Wales and Northern Ireland. 

BBC News Channel

Attorney General Jeremy Wright, speaking on behalf of the government outside the Supreme Court, said "the government is disappointed with the outcome" of the judgement, but it will do everything it can "to comply with it".

He said the court made clear it was not trying to reverse the Brexit decision, but added that it will now "be a political matter and not a legal matter".

He added that Brexit Secretary David Davis will make a further statement in Parliament later today.

Lord Neuberger says any changes to the UK's constitutional arrangements "require such changes to be authorised by an Act of Parliament".

Supreme Court president Lord Neuberger says:

The decision means that Parliament must vote before the UK government begins the Article 50 process of leaving the EU.

In a round-table debate on BBC's Victoria Derbyshire programme, former Labour leadership contender Owen Smith said his party will try to hold the government to account by making amendments to any bill on Brexit that goes through Parliament.

But he added: 

UKIP member Suzanne Evans said if either house decides to vote against the will of the people it will trigger a General Election.

She adds that if the House of Lords decides to vote that way, they will be "signing their own death warrant".

Liberal Democrat Tom Brake says there should be a second vote on the terms of the deal and if his party does not get that, it will be voting against triggering Article 50.

Victoria Derbyshire

Clive Coleman, the BBC's legal affairs correspondent, said the Supreme Court judgement "is quite simply the biggest case about where power lies in our constitution".

He says "this is a case that will define the limits of executive power", between ministers on the one hand and Parliament on the other.

The government wants to trigger Article 50 using prerogative powers because it involves an international treaty.

But Clive says the investment manager Gina Miller, who brought the case against government, says "no, what's at stake here is people's rights".

The ruling will come from the president of the court, Lord Neuberger, who is expected to take five minutes reading out a summary of the court's findings.

Clive says Lord Neuberger will say if there are dissenting judgments, adding that its unprecedented that 11 judges were involved in hearing the case.

The home secretary appears to rule out the possibility of Scotland being handed powers over immigration after the UK leaves the EU.

The Guardian

Image source, EPA

According to The Guardian, external, victory for the prime minister at the Supreme Court would deliver the simplest and most direct approach to initiating Article 50 of the treaty on European Union, external, which formally begins the UK’s departure from the EU.

The paper says that if, despite politically managed expectations, the 11 justices decide that the royal prerogative powers are sufficiently extensive, then she would not have to consult Parliament and could proceed immediately to Brussels without bothering to secure parliamentary approval.

A surprise victory for the government at this late stage seems unlikely, the Guardian adds, and would be met with head-scratching in No 10, which has already conceded that Parliament should be consulted at the end of the Brexit process.

The paper says the more widely expected outcome is that the justices, by a significant majority, follow the High Court’s earlier ruling , externaland declare that the government’s executive powers to sign international treaties, as inherited through the royal prerogative, do not extend to uprooting parliamentary legislation such as the European Communities Act of 1972, which delivered specific rights to British citizens.

Read more, external

Image source, PA

With her Brexit speech last week, Theresa May revealed some key details about her approach to negotiations with the EU.

Here's what we know now:

Leaving the single market

What it is: The single market aims to make it easy for EU nations to trade with one another. It allows free movement of goods, workers, services and capital around the EU, without any tariffs, pretty much as if it was all one country. While it remains in the EU, the UK is a full member of the single market, and much of the Brexit debate has been about what will happen when it leaves. Some non-EU countries - such as Norway - have arrangements with the EU that allow them to be part of the single market if they meet certain conditions.

UK government position: Having previously not publicly committed either way, Theresa May confirmed the UK cannot remain a member of the single market after it leaves the EU.

She said this was because, as European leaders have stressed, the UK would have to accept EU rules and regulations and be bound by the European Court of Justice.

Instead, she said, the UK will push for a new "comprehensive free trade agreement", giving it "the greatest possible access" to the single market.

Read more on what we now know about the UK's Brexit plan

Image source, Getty Images

What does Brexit mean?

It is a word that has become used as a shorthand way of saying the UK leaving the EU - merging the words Britain and exit to get Brexit, in a same way as a possible Greek exit from the euro was dubbed Grexit in the past.

Why is Britain leaving the European Union?

A referendum - a vote in which everyone (or nearly everyone) of voting age can take part - was held on Thursday 23 June, to decide whether the UK should leave or remain in the European Union. Leave won by 52% to 48%. The referendum turnout was 71.8%, with more than 30 million people voting.

Read more of your questions answered